What Is a Second Order Reaction?

A chemical reaction can be classified either according to its molecularity or according to its order. The order is a description of the number of concentration terms multiplied together in the rat equation. Order is the number of concentration factors in the rate equation. The order of a reaction can only be found by experiment and cannot be worked out from the equation of the reaction.

“A reaction whose rate depends upon the second power of the concentration of the reactant is called second order reaction.”

In the second order reaction
A + B -->  Products

The rate equation is
Rate = - d[A]/dt = - d[B]/dt = k[A][B] or rate(for one type of reactants) = [A]^2

For the second order reaction, the rate of reaction increases with the concentration of reactants. In second order reaction the rate of reaction is proportional to the concentration of reactant. When a reaction is second order in a reactant, the doubling its concentration increases rate by a factor 22 and tripling the concentration increases rate by 32 and so forth.

The rate of a reaction depends on concentration but rate constant is independent of concentration. The rate as well as the rate constant are affected by temperature and catalyst.

For example, saponification of ethyl acetate, the chemical equation for this reaction is
CH_3COOC_2H_5 + NaOH --> CH_3COONa + C_2H_5OH

The molecules (CH_3COOC_2H_5 + NaOH) are involved in this reaction and hence the molecularity of the reaction is two. This rate of this reaction has been found to obey the following rate.

-d[CH_3COOC_2H_5]/dt a [CH_3COOC_2H_5][NaOH]

Hence the order to this reaction is two.

What Oxidation Means in Chemistry?

In our daily life we come across processes like rusting of objects made of iron, fading of the color of clothes, burning of the combustible substances such as cooking gas, wool, coal etc. What is happening behind these changes? These process fall in the category of specific type of chemical reactions called oxidation-reduction reactions.

Oxidation is the most important high temperature reaction. Oxidation refers to an increase in oxidation state, which means a loss of electrons. In organic chemistry it is often easier to view oxidation as increasing the number of bonds to oxygen or other heteroatoms. Simply oxidation is a process of addition of oxygen or removal of hydrogen to a substance.

An oxidation reaction between a metal (M) and the oxygen (O_2) can be written as 

M(s) + O_2 (g) \rightarrow MO_2(s).
Some of the examples of oxidation reaction are listed below.

1. Rusting of iron - In rusting, iron does not combine directly with oxygen but involves the oxidation of iron in an electrochemical process.
2. Digestion of food in our body - When foods are broken down inside the body during the course of normal digestion oxidation also takes place, the vital difference is that the food energy is made available for our use.
3. Burning of fuels - The combustion of fuels is an oxidation reaction. The combustion of hydrocarbon fuels is a vital source of energy in our economy. Daily we make use of combustion of fuels. In respiration the combustion of foods provides us with energy.
4. Rancidity - The condition produced by aerial oxidation of fats and oils in foods marked by unpleasant smell and taste is called rancidity.

Why Veins Look Blue?

Vein Looks Blue

Are veins blue in real life? If you look at the palm side of your wrist, you can see the veins, they too are blue. The vessels that bring blood toward the heart are veins. Veins carry deoxygenated blood back to the heart and their pressure is significantly lower than in arteries. Veins have valves that help keep the blood moving toward the heart in the one way circuit.

Red blood cells are important because they carry oxygen to other cells. They do this with the help of a protein called hemoglobin. This protein contains iron and can capture tiny particles or molecules of oxygen. Hemoglobin proteins that contain oxygen make red blood cells red. When hemoglobin molecules don’t contain oxygen, red blood cells are blue. This is why vein looks blue.

A simpler test can confirm that though your eyes and brain perceive blue, the vein is actually a pinkish flesh color. The test requires two pieces of standard gray duct tape. Place one piece of the duct tape on each side of the vein, covering the adjacent skin. Once you see the vein all by itself, you can see its real color, a shade of pink.

It is considered that the oxygenated blood in the arteries is red, and that the deoxygenated blood in the veins is blue. While it is true that the oxygenated blood in the arteries is a bright red color, the blood in the veins is also a red color not blue. Why does the blood trickling out of a cut vein look bright rad? Because the moment the dark purplish blood hits the air, it mixes with oxygen and changes color.

How to Find pOH

The pH and pOH of a neutral solution at 25oC are equal to 7. The ion concentrations are small and the negative exponents make them tedious to work. Soren Peer Lauritz Sorenson, a Danish biochemist devised the pH concept in 1909 to express hydrogen ion concentration. The pOH of a solution can be defined as

pOH = - log[OH^-]
The [H+] and [OH-] are inversely related and consequentially pH and pOH are inversely related. We can picture pH and pOH as sitting on opposite sides of a seesaw as one goes up the other always goes down. The product of the hydrogen and hydroxide concentrations will be equal to 1.0 x 10-14, while the sum of the pH and pOH will be equal to 14.

The relationship between the type of solution, pOH and ion concentration is shown in the table below.

The pH and pOH scales are based on logarithms, a change in 1 pH or pOH unit represents a change in ion concentration of a factor of ten. For example, coffee with a pH of 5 has approximately 100 times the hydronium ion concentration as tap water with a pH of 7.

The concept of alkalinity is much less commonly used; it is defined as the logarithm of the reciprocal of the concentration of hydroxyl in a solution. The following are the formulas used to determine the pOH.

pOH = 14 – pH
pOH = - log [OH^-]

What an Electron Domain Means in Chemistry

An electron domain is any region of space around the central atom in which there is a high probability of finding electrons. A domain of electrons, two electrons in a nonbonding domain sometimes called a lone pair, two electrons in a single bond domain, four electrons in a double bond domain, six electrons in a triple bond domain tends to repel other domains of electrons. Domains of electrons around a central atom will orient themselves to minimize the electron-electron repulsion between the domains.

The number of atoms that a central atom is attached to plus the number of unshared electron pairs that an atom may have. The atom bonded to the central atom by a single or a double or a triple bond is still counted as one electron domain. The geometry of the molecule can then be predicted on the basis of the repulsion of electron domains and the relative magnitudes of these repulsions.

Bonding electron domain is of three types. Single bond (1 pair, 2 electrons); double bond (2 pairs, 4 electrons); triple bond (3 pairs, 6 electrons). Non-bonding electron domains is the pair of valence electrons not involved in a bond.

For example, take NH3. Here the nitrogen has five valence electrons and these five electrons are placed in four hybrid atomic orbitals. N has attached to it three H atoms by three shared electron pairs and therefore N has one unshared electron pair or non-bonded electron pair left. Thus the central atom nitrogen N has a total of four electron domains that is three bonded pairs and one non-bonded electron pair.

Why Do We Smell When We Sweat?

When people exposed to heat, through experiencing elevated air, temperature, exercise or emotional stress, they often sweat. Sweating is the body’s way of cooling itself off, whether a person is stressing over a big test. Sweat comes from the 2.6 million sweat glands in the skin. However, the degree to which people sweat and the resulting smell that is produced varies greatly.

The skin has two types of sweat glands: eccrine and apocrine. The skin contains millions of eccrine glands distributed all over the body, and the fluid that they produce consists mainly of salt and water and has no smell. Appocrine glands meanwhile tend to locate in areas where there are lot of hair follicles and the sweat they produce is fatty.

Sweat only begins to smell and cause the unpleasant odors when the bacteria living on our skin and clothes deign to break it down to produce the fatty acids they feed on. Sweat is almost completely of water with tiny amounts of other chemicals like ammonia, urea, salts and sugar. When the sweat hits the air, the air makes it evaporate. As the sweat evaporates off the skin and cool down.

Sweat itself is odorless whether it comes from the armpits or other areas of the body. The smelliness begins when sweat mixes with bacteria that occur naturally on the surface of the skin. This distinctive odor is called bromhidrosis -foul smelling sweat.

How pH and pKa Are Related?

pH vs pKa

pH is a measure of the concentration of hydrogen ions in an aqueous solution. pKa (acid dissociation constant) is related, but more specific, in that it helps you predict what a molecule will do at a specific pH. Essentially, pKa tells you what the pH needs to be in order for a chemical species to donate or accept a proton.

• The lower the pH, the higher the concentration of hydrogen ions, [H+]. The lower the pKa, the stronger the acid and the greater its ability to donate protons.
• pH depends on the concentration of the solution. This is important because it means a weak acid could actually have a lower pH than a diluted strong acid. For example, concentrated vinegar (acetic acid, which is a weak acid) could have a lower pH than a dilute solution of hydrochloric acid (a strong acid). On the other hand, the pKa value is a constant for each type of molecule. It is unaffected by concentration.
• Even a chemical ordinarily considered a base can have a pKa value because the terms "acids" and "bases" simply refer to whether a species will give up protons (acid) or remove them (base). For example, if you have a base Y with a pKa of 13, it will accept protons and form YH, but when the pH exceeds 13, YH will be deprotonated and become Y. Because Y removes protons at a pH greater than the pH of neutral water (7), it is considered a base.

Relating pH and pKa With the Henderson-Hasselbalch Equation

If you know either pH or pKa you can solve for the other value using an approximation called the Henderson-Hasselbalch equation:

pH is the sum of the pKa value and the log of the concentration of the conjugate base divided by the concentration of the weak acid.

At half the equivalence point:

pH = pKa

It's worth noting sometimes this equation is written for the Ka value rather than pKa, so you should know the relationship:

pKa = -logKa

Assumptions That Are Made for the Henderson-Hasselbalch Equation

The reason the Henderson-Hasselbalch equation is an approximation is because it takes water chemistry out of the equation. This works when water is the solvent and is present in a very large proportion to the [H+] and acid/conjugate base. You shouldn't try to apply the approximation for concentrated solutions. Use the approximation only when the following conditions are met:

• -1 < log ([A-]/[HA]) < 1
• Molarity of buffers should be 100x greater than that of the acid ionization constant Ka.
• Only use strong acids or strong bases if the pKa values fall between 5 and 9. Continue reading..

What causes Hospital Smell?

If you stepped into the hospital, you can immediately notice a peculiar corrosive smell? What makes hospital to smell like that? Is it the smell of diseases? No, it is the smell of disinfectant that hospitals prefer to use to make the place clean and free from bacteria and viruses.

Louis Pasteur first observe that phenol kills bacteria and he used this substance to produce vaccines. This observation lead to develop the first antiseptic wound treatment in 1867.By spraying infected open leg fractures with aqueous phenol solution (carbolic acid), he could lower the mortality from such wounds from 60% to 10%. As a result carbolic acid was used over decades for the disinfection of hospitals and operating theaters, causing the typical unpleasant hospital smell.

Some of the other disinfectant used in hospitals which gives specific odor are given below.

Disinfectant used in Hospitals

 

The sense of smell is not considered adequate warning for the presence of hazardous materials. By the time you smell a chemical you are being exposed. In addition, many chemicals cause olfactory fatigue and deaden the sense of smell. Another substance which is responsible for hospital smell is iodoform. It is produced from ketones and is a pale yellow insoluble solid with a sweet antiseptic “hospital smell”.

Exposure to phenol through inhalation also leads to adverse health effects. Inhalation causes severe irritation of the respiratory tract with coughing, burns and breathing difficulty. Hospital smell a medley of sanitizers, chemicals and bodily fluids that causes many people to experience a vague sense of dread, unease and stress.

The Chemistry behind Artificial Sweeteners

Natural sweeteners for example, sucrose and fructose add to calorie intake and therefore may people prefer to use artificial sweeteners. Many people find artificial sweeteners to be an attractive alternate to the natural and calorie contributing counterparts. No acceptable general theory can explain what makes certain compounds taste sweet and precisely how they interact with human taste sensing systems.

Natural Sweeteners also increase the glucose level in persons suffering from diabetes. So to assist in weight loss and to manage diabetes mellitus people have been looking for artificial sweetener. These are duplicates of sugar and have less food energy called non-nutritive sweeteners. Some commonly used sugar substitutes are given below.

• Saccharin – Saccharin is about 550 times sweeter than sucrose. It is not biodegradable ad is excreted as such in urine. It has no calorie content. It has been proved to be a life saver for countless diabetes and is useful for those who need to control intake of calories.
• Aspartame – It is most widely used artificial sweetener. It is a methyl ester of a dipeptide unrelated to any carbohydrate. Aspartame is about 100 times as sweet as sucrose. It decomposes at baking or cooking temperature and hence can be used in cold foods and soft drinks.
• Cyclamate – It is low calorie additives with an intense sweetness. It was water soluble, cheaply produced and for almost two decades in combination with saccharin in sweet N low until evidence surfaced that it caused cancer in mice if consumed in vast amounts. It was banned by FDA in 1969 however, it is still available in some countries.
• Sucralose – It is relatively new artificial sweetener that was approved for use in USA. It is proposed to be as 600 times sweeter than sucrose. It is produced by chlorinating sucrose.

Does artificial sweeteners provide any benefits to humans? Is it safe for the environment? Have any long term studies been conducted on human consuming this artificial sugar? Unfortunately the answer to all of these questions is a resounding no! Better avoid using artificial sweeteners.

How To Succeed in Organic Chemistry Class?

Organic chemistry is often considered the hardest chemistry class. It's not that it's impossibly complicated, but there is a lot to absorb, in both the lab and classroom, plus you can expect to do some memorization to succeed at exam time. If you're taking o-chem, don't stress! Here are survival tips to help you learn the material and succeed in the class.

1) Choose How To Take Organic Chemistry

Are you more of a mental sprinter or is distance running your style? Most school offer organic chemistry one of two ways. You can take the year-long course, broken into Organic I and Organic II. This is a good choice if you need time to digest and learn material or master lab protocols. It's a good choice if you tend to ask a lot of questions, because your instructor will be able to take the time to answer them. Your other option is to take organic over the summer. You get the whole shebang in 6-7 weeks, sometimes with a break in the middle and sometimes straight through, start to finish.

If you're more of a cramming, run-to-the-finish type of student, this may be the way to go. You know your study style and level of self-discipline better than anyone else. Choose the learning method that works for you.

2) Make Organic Chemistry a Priority

Your social life may take a hit while you're taking organic. It won't be your first chemistry class, so you already expect that. Try to avoid taking other challenging courses at the same time. There are only so many hours in the day to work problems, write lab reports, and study. If you load your schedule with sciences, you're going to get pressed for time. Plan to give time to organic. Set aside time to read the material, do the homework, and study. You'll also need some downtime to relax. Getting away from it for a while really helps the material "click". Do not expect to just go to class and lab and call it a day. One of the biggest survival tips is to plan your time.

(3) Review Before and After Class

I know... I know... it's a pain to review general chemistry before taking organic and to review notes before the next class. Reading the textbook? Agony. Yet, these steps truly help because they reinforce material. Also, when you review the subject, you may identify questions to ask at the beginning of class. It's important to understand each part of organic because topics build on those you have already mastered. Continue reading..

3 Ways to Find the Volume in a Test Tube

Finding the volume of a test tube or NMR tube is a common chemistry calculation, both in the lab for practical reasons and in the classroom to learn how to convert units and report significant figures. Here are three ways to find the volume.

Calculate Density Using Volume of a Cylinder

A typical test tube has a rounded bottom, but NMR tubes and certain other test tubes have a flat bottom, so the volume contained in them is a cylinder. You can get a reasonably accurate measure of volume by measuring the internal diameter of the tube and the height of the liquid.

The best way to measure the diameter of a test tube is to measure the widest distance between the inside glass or plastic surfaces. If you measure all the way from edge to edge, you'll include the test tube itself in your measurements, which isn't correct.

Measure the volume of the sample from where it starts at the bottom of the tube to the base of the meniscus (for liquids) or the top layer of the sample. Don't measure the test tube from the bottom of the base to where it ends.

Use the formula for the volume of a cylinder to perform the calculation:

V = pi r^2 h

where V is volume, pi is 3.14 or 3.14159, r is the radius of the cylinder and h is the height of the sample

The diameter (which you measured) is twice the radius (or radius is one-half diameter), so the equation may be rewritten:

V = pi (1/2 d)^2 h

where d is diameter.

Example Volume Calculation

Let's say you measure an NMR tube and find the diameter to be 18.1 mm and height to be 3.24 cm. Calculate the volume. Report your answer to the nearest 0.1 ml.

First, you'll want to convert the units so they are the same. Please use cm as your units, because a cubic centimeter is a milliliter! This will save you trouble when it comes time to report your volume. Continue reading..

The Chemistry that brews in your Cup of Coffee

Does coffee have anything to do with chemistry? Yes it is. We often think chemistry is made of explosions and color changing liquids and those incredibly hard to pronounce chemical names. Well chemistry is all those things and much more. It is about the interactions of atoms and molecules. Chemistry is all around us all the time. Making coffee is chemistry.

Brewing coffee is half art and half chemistry. The exact portions of ground coffee to water, the water temperature and the water contact time with the grounds ass affect the flavor of the final coffee. Brewing of coffee depends on two factors, first the heat contained in the brewing water has a big influence on the extraction. Hot water with high energy can extract more coffee solids faster than colder water because energy facilitates molecular movement faster.

Coffee contains a complex combination of carbohydrates, lipids, proteins, amino acids, nucleic acids, vitamins, inorganic compounds, alkaloids and volatile compounds. In all coffee contains more than 1000 different chemical compounds around 800 are volatile chemicals that dissipate rapidly. Coffee rich aroma results from the mixture of about 50-60 volatile chemicals released during brewing.

Water acts as a solvent doing the work of extracting the flavors in the coffee during the brewing process. This is where the quality of the water plays important role as the hardness and the mineral content can significantly affect how coffee brews. Harder water seems to change the rate at which the soluble in the coffee go into solution. Hard water does a poor job of brewing coffee.

What is a Molecule?

 

What Is a Molecule?

The terms molecule, compound, and atom can be confusing! Here's an explanation of what a molecule is (and is not) with some examples of common molecules.

Molecules form when two or more atoms form chemical bonds with each other. It doesn't matter if the atoms are the same or are different from each other.

Examples of Molecules

Molecules may be simple or complex. Here are examples of common molecules:

• H2O (water)
• N2 (nitrogen)
• O3 (ozone)
• CaO (calcium oxide)
• C6H12O6 (glucose, a type of sugar)

Molecules Versus Compounds

Molecules made up of two or more elements are called compounds. Water, calcium oxide, and glucose are molecules that are compounds. All compounds are molecules; not all molecules are compounds.

What Is Not a Molecule?

Single atoms of elements are not molecules. A single oxygen, O, is not a molecule. Continue reading..

What makes a Neon Light Glow?

Have you ever seen a colorful glowing tube of light in a store’s front window or outside a restaurant, the glow is due to some noble gases which emits. These glowing tubes are called neon lights. Neon lights are commonly seen on advertising hoardings, outside shops, restaurants and cinemas. Their color is so distinctive that to most people the word “neon” has come to mean a dark pink glow, although neon is merely an elemental rare gas element.

The technology behind how a neon light works is very different from that of normal incandescent lights. Electroluminescence or the conversion of electricity directly into light is the operating principle of neon lights.

• A neon light consists of a glass tube filled with a noble gas at a very low pressure.
• Neon lights containing the other noble gases are also common.
• Neon is wholly colorless if placed in a normal flask, yet to glow of an eon light is visible even at night, so its color cannot be due to the way it interacts with light.
• Metal plates called electrodes are fitted to each end of the gas filled tube.
• When the neon light is plugged into an electricity supply, an electrical current flows through the tube between the electrodes.
• Gas discharge takes place and collisions involving mobile electrons generally elastic. They bounce like a ball off a wall.
• An extreme voltage ionizes the neon to form a plasma of Ne⁺ and e^-. Inelastic collision between Ne+ and neutral atom allow for the release of energy as visible light.
• Neon atoms are neutral, but ionization of the gas phase neon forms Ne+ ions, so the tube contains a mixture of electrons and ions.

Ne⁰(g) --> Ne⁺(g) + e^-

Thus neon light glows because they emit light under suitable conditions. All the light we see id a result of electrons jumping between electron shells. Subsequent relaxation of the electron releases a photon of light. It is this emission that we see as the bright glow of neon light.

How is Calcium Vital to the Body, especially Teeth?

Teeth are made of calcium

Calcium is the first thing we think we think of when we think about minerals. Calcium is the most prevalent mineral in out body, making up about two percent of our body weight. An adult has about 1.2kg of calcium in the body, 99% of this amount is in our bones and teeth. Calcium is vital for strong bones and healthy teeth, the transmission of nerve impulses, blood clotting, and the regulation of blood pressure and muscle contraction.

Although the major part of the body’s calcium is in bones, the most important functions of calcium are in the maintenance of muscle contractility and responses to hormones and neurotransmitters. To maintain these essential regulatory functions, bone calcium is mobilized in deficiency so and to ensure that the plasma and intercellular concentrations are kept within a strictly controlled range.

Many factors affect our calcium status. Vitamin D enhances the absorption of calcium and too much vitamin D combined with excess calcium intake can increase the risk of forming kidney stones. A high protein or high sugar diet can deplete calcium reserves in the body.


Because calcium is so important in keeping the human body functioning properly, it is important component of the daily diet of all people. It is especially important for children and pregnant women because it promotes the growth and heath of bones and teeth.  Foods rich in calcium include cheese, milk, yogurt and leafy greens such as spinach.

Few Facts About Fuel Cells

Fuel cell used in Car.

A fuel cell is a device that uses hydrogen and oxygen to create electricity by an electrochemical process.  A fuel cell consists of two electrodes a negative and a positive electrode which is sandwiched around an electrolyte. Fuel cells have been hot topics in discussions about renewable energy themselves, rather they are an efficient way of generating electricity with low emissions.

Some of the facts about fuel cells are:

1. Their electric efficiency is very high, especially under partial load.
2. They are extremely clean. If hydrogen is used, the only product is pure water, but even if hydrocarbons are used no pollutants are emitted.
3. They do not have any moving parts and are therefore quiet.
4. Different types of fuel cells allow different fuels to be used – from pure hydrogen to natural gas, methanol, biogas and testified coal.
5. Their modular design allows them to be built according to specific power requirements.
6. At present fuel cells are a potentially disruptive technology since it is still unclear whether they can develop quickly enough with performance characteristics to meet the needs.
7. The pre commercialization stage and the future development of this technology remain uncertain. It remains about their commercialization and their costs remain high compared to existing incumbent technologies.
8. A long transition process will be required before the hydrogen economy becomes a reality. In the long term there will be an obvious co-evolution between the successful commercialization of fuel cells and the deployment of hydrogen energy networks.

Fuel cell can be used in many ways. Stationary applications as cogeneration units, mobile applications in the transport sector hydrogen cars and small fuel cells for portable appliances notebook power supplies etc are some of the most common examples.

The Chemistry of Correction Fluid

Correcting spelling from correction fluid.

Correction fluids are solvents used to remove or bleach ink so it will not be seen on the paper or writing surface. Different solvents react differently to ink formulations, chemicals in the paper etc. Solvents that are a mixture of common household chemicals, commercial ink eradicators or even uncommon chemicals such as brake fluid etc.

Bette Nesmith Graham was born on 23 March 1324 in Dallas, Texas. She invented the correction fluid which she called “Mistake out”. In 1971 Johanknecht and his partners incorporated their new business, white out products, Inc providing correction fluid to users all over the world. Correction fluids usually contain a proprietary mixture of solvents and whiteners that act much like a thin fast drying paint. Typically methyl chloroform is used as a fast drying solvent in which pigments such as titanium dioxide and other colorants are suspended.

Correction fluid may be spirit or water based, if the spirit based liquid is used, it is necessary to add thinner to the bottles as after a time the original liquid tends to thicken. Spirit based liquid dries more quickly than water based. It is produced in various shades to match the typing paper and is applied with a small brush.

In halation of large amounts of solvents vapour may cause unconsciousness and may irritate the mucus membranes of susceptible individuals. It can also have a long term effect on the central nervous system and cause abnormal heartbeats in humans. The dried correction fluid can be especially hazardous if burned, releasing small amounts of phosgene, hydrogen chloride and chlorine. The formula will react with strong bases and oxidizing agents as well as reactive metals.

Is Dihydrogen Monoxide or DHMO Dangerous?

Every now and then (usually around April Fools Day), you'll come across a story about the dangers of DHMO or dihydrogen monoxide. Yes, it's an industrial solvent. Yes, you're exposed to it every day. Yes, it's true. Every one who ever drinks the stuff eventually dies. Yes, it's the number one cause of drowning. Yes, it's the number one greenhouse gas.

Dihydrogen Monoxide

Other uses include:

• flame retardant chemical
• food additive
• component of pesticide sprays
• torture in World War 2 prison camps
• to make chemical and biological weapons

But is it really so dangerous? Should it be banned? You decide.



Here are the facts you should know, starting with the most important one:

Dihydrogen Monoxide or DHMO Common Name: water

DHMO Chemical Formula: H2O

Melting Point: 0 °C, 32 °F

Boiling Point: 100 °C, 212 °F

Density: 1000 kg/m3, liquid or 917 kg/m3, solid. Ice floats on water.

So, in case you haven't figured it out yet, I'll spell it out for you: Dihydrogen monoxide is the chemical name for ordinary water.

Instances Where Dihydrogen Monoxide Really Can Kill You

For the most part, you're fairly safe around DHMO. There are, however, certain situations where it truly is dangerous:

1. While dihydrogen monoxide contains oxygen, each molecule only contains one atom. You need O_2 to breathe and carry on cellular respiration. So, if you try to breathe water, you could die.
2. If you drink too much water, you can suffer a condition called water intoxication or hyponatremia. People have died from it.   
3. There are different forms of water. Heavy water has the exact same molecular structure as regular water, except one or more of the hydrogen atoms is replaced with deuterium. Deuterium is hydrogen, but each atom contains a neutron. You naturally drink a tiny bit of heavy water with regular water, but if you drink too much of the stuff, you'll die. How much? Continue reading..

Why Ice Cubes are Cloudy on the Inside?

Take an ice cube and observe it carefully, you will notice that it is somewhat cloudy. If the water is pure then liquid water should freeze as a clear solid, but ice cubes commonly have a cloudy appearance. Why is it so? And what makes the Ice cube looks cloudy? This leads to some interesting facts.

The cloudy appearance of the ice cube is due to the presence of imperfections that is air bubbles. As ice forms pure water solidifies leaving the dissolved gases and salts in solution. Thus the freezing process concentrates the dissolved species in smaller and smaller volumes of liquid solution effectively increasing their concentration. With a higher concentration of dissolved material the temperature at which additional ice will form is lowered. The cloudiness in the center of an ice cube thus is the consequence of the concentration dissolved gases and minerals that refract light and create an opaque appearance.

Ice Cubes are Cloudy on the Inside

Ice cubes can appear cloudy for other reasons too. If the freezer compartment is opened as lot, water vapor will condense on top of the ice cube tray to form a fine frost. And if the water is oxygenated as if it run into the trays from a spraying tap, it will also form ice that looks milky rather than clear.

What are the Branches of Chemistry?

There are several branches of chemistry. Here is a list of the main branches of chemistry, with an overview of what each branch of chemistry studies.

Agrochemistry - This branch of chemistry may also be called agricultural chemistry. It deals with the application of chemistry for agricultural production, food processing, and environmental remediation as a result of agriculture.

Analytical Chemistry - Analytical chemistry is the branch of chemistry involved with studying the properties of materials or developing tools to analyze materials.

Astrochemistry - Astrochemistry is the study of the composition and reactions of the chemical elements and molecules found in the stars and in space and of the interactions between this matter and radiation.

Biochemistry - Biochemistry is the branch of chemistry concerned with the chemical reactions that occur inside living organisms.

Chemical Engineering - Chemical engineering involves the practical application of chemistry to solve problems.

Chemistry History - Chemistry history is the branch of chemistry and history that traces the evolution over time of chemistry as a science. To some extent, alchemy is included as a topic of chemistry history.

Cluster Chemistry - This branch of chemistry involves the study of clusters of bound atoms, intermediate in size between single molecules and bulk solids.

Combinatorial Chemistry - Combinatorial chemistry involves computer simulation of molecules and reactions between molecules.

Electrochemistry - Electrochemistry is the branch of chemistry that involves the study of chemical reactions in a solution at the interface between an ionic conductor and an electrical conductor. Electrochemistry may be considered to be the study of electron transfer, particularly within an electrolytic solution.

Environmental Chemistry - Environmental chemistry is the chemistry associated with soil, air, and water and of human impact on natural systems.

Food Chemistry - Food chemistry is the branch of chemistry associated with the chemical processes of all aspects of food. Many aspects of food chemistry rely on biochemistry, but it incorporates other disciplines as well.

General Chemistry - General chemistry examines the structure of matter and the reaction between matter and energy. It is the basis for the other branches of chemistry.

Geochemistry - Geochemistry is the study of chemical composition and chemical processes associated with the Earth and other planets.

Green Chemistry - Green chemistry is concerned with processes and products that eliminate or reduce the use or release of hazardous substances. Remediation may be considered part of green chemistry. Continue reading..

Why are Liquid Crystals so Interesting?

Liquid Crystals

Liquid crystals are used in many displays. They are important because of the richness of structures and transitions. Liquid crystals are relatively large regions of molecules which point in the same direction, and so have a structure analogous to ordinary crystals. Lehmann first referred to them as flowing crystals and later used the term “liquid crystals”.

Liquid crystals are best known for their use in displays in which an electric field darkens parts of the display to produce numbers letters or patterns by rotating some of the molecules away from the direction of their neighbors. The liquid crystals obtained by two methods called thermotropics and lyotropics.

The process of liquid crystalline solutions and melts reveals some interesting facts. The most important observation is that fibers and injection molded specimens are highly oriented. Molecular orientation in the solid state comes directly from flow induced orientation since no further drawing of the specimens occurs. Because of the direct correlation of flow history to structure property relations and understanding of the rheological properties of these systems is essential.

Liquid crystals can be composed both of polar and apolar molecules. An important fact in connection with polar substances is that in uniaxial phases there is no polar ordering of the molecules. In addition, liquid crystals are anisotropic materials, hence their linear optical properties are determined by a symmetrical dielectric tensor rather than a scalar refractive index.

How to Calculate Theoretical Yield of a Chemical Reaction?

The theoretical yield of a chemical reaction is the product calculated by assuming that the reaction goes to completion. In reality, all of the reactants are not consumed and all of the products are not recovered. Thus a certain percentage of the products are recovered. This is called the percent yield. Theoretical yield is the amount of product we would recover if 100% of the reactant reacted. The maximum amount of product that can be produced from given amounts of reactant.

The term percent yield is used to indicate how much of a desired product is obtained from a reaction.

Theoretical yield of product = actual yield of product/Percent yield x 100%

Let’s solve a problem based on theoretical yield.

Problem: Consider the following reaction.
C₂H₅OH + CH₃COOH --> CH₃COOC₂H₅ + H₂O

If the yield of ethyl ethanoate obtained when 20.00g of ethanol is reacted with excess ethanoic acid is 30.27g. Calculate the theoretical yield.

Solution:

Molar mass of C₂H₅OH = 46.08 g/mol

Number of moles of C₂H₅OH = 20.00/46.08 = 0.4340 mol

The molar mass of CH₃COOC₂H₅ = 88.12 g/mol

The mass of ethyl ethanoate CH₃COOC₂H₅ = 0.4340 x 88.12 = 38.24g.

Therefore the theoretical yield is 38.24g.

Is Vitamin C an Organic Compound?

Yes, vitamin C is an organic compound. Vitamin C, also known as ascorbic acid or ascorbate, has the chemical formula C₆H₈O₆. Because it is comprised of carbon, hydrogen, and oxygen atoms, vitamin C is classified as organic, whether or not it comes from a fruit, is made within an organism, or is synthesized in a laboratory.

What Makes Vitamin C Organic?

In chemistry, the term "organic" refers to carbon chemistry. Basically, when you see carbon in a compound's molecular structure, this is a hint you're dealing with an organic molecule. However, simply containing carbon isn't sufficient, as some compounds (e.g., carbon dioxide) are inorganic. Basic organic compounds also contain hydrogen, in addition to carbon. Many also contain oxygen, nitrogen, and other elements, although these aren't essential in order for a compound to be classed as organic.

You may be surprised to learn vitamin C isn't just one specific compound, but rather, a group of related molecules called vitamers.

The vitamers include ascorbic acid, the ascorbate salts, and oxidized forms of ascorbic acid, such as dehydroascorbic acid. In the human body, when one of these compounds is introduced, metabolism results in the presence of several forms of the molecule. The vitamers act primarily as cofactors in enzymatic reactions, including collagen synthesis, antioxidant activity, and wound-healing. The molecule is a stereoisomer, where the L-form is the one with biological activity. The D-enantiomer is not found in nature, but can be synthesized in a lab. When given to animals that lack the ability to make their own vitamin C (such as humans), D-ascorbate has less cofactor activity, even though it is an equally potent antioxidant.

What About Vitamin C from Pills?

Man-made or synthetic vitamin C is a crystalline white solid derived from the sugar dextrose (glucose). One method, the Reichstein process, is a combined microbial and chemical multi-step method of producing ascorbic acid from D-glucose. The other common method is a two-step fermentation process. Industrially synthesized ascorbic acid is chemically identical to vitamin C from a plant source, such as an orange. Plants typically synthesize vitamin C by enzymatic conversion of the sugars mannose or galactose into ascorbic acid.  Continue reading..

What are Types of Solutions in Chemistry?

Solutions are homogeneous mixtures of two or more than two components. By homogeneous mixture it is meant that composition and properties are uniform throughout the mixture. Components of solution are called solute and solvent. Every solution is made up of a solvent and one or more solutes.

If water is the solvent, the solutions are called aqueous solutions and solutions in which other solvents like benzene, ether etc are used are called non-aqueous solutions. A solution containing one solute dissolved in a solvent is called a binary solution that is consisting of two components. Here each component may be solid, liquid or in gaseous state which is summarized in the table below.

Most chemical reactions are carried out in solutions. Body fluids are also solutions of various components in water. The most common types of solutions used in chemistry labs are solid-liquid, liquid-liquid and gas-liquid solutions. Thus a solution plays an integral part of lives.

What are Some Examples of Antiseptics?

Antiseptics also known as bacteriostatic agents inhibit the growth of germs but do not kill, microorganisms. Antiseptic generally applied to the skin or mucous membranes. Some also are used as cleansing agents. Some antiseptic such as iodine and hydrogen peroxide operate by oxidizing and thus destroying compounds essential to the normal functioning of bacteria.

Example of Antiseptic

Examples of Antiseptics

Some examples of antiseptics are given below:

• Soap – Some soaps contains small amounts of antiseptic substances which inhibits but not kill bacteria and fungi. The most frequent added antiseptic to soap are triclosan, triclocarbon, chloroxylenol. But usually soaps containing antiseptics are not recommended.

• Methylated spirits – Industrial methylated spirit is used as a rapid antiseptic in neonatal intensive care prior to invasive procedures such as venipuncture or lumbar punctures. It is also used with other antiseptics such as iodine or chlorohexidine.

• Hydrogen peroxide – Hydrogen peroxide has been commonly used as an antiseptic for all types of wounds as an adjunct to surgery, and as a treatment for chronic conditions. It is also used in the treatment of periodontal diseases and for root canal debridement during endodontic therapy.

• Dettol (a mixture of chloro xylenol and terpeneol in a suitable solvent) – Dettol was bactericidal against the wide range of microorganism tested, achieving a complete kill of the inoculum within 10min at dilutions in excess of the recommended use dilution.

• Tincture – Tincture is a renowned antiseptic against all internal and external infections. When tincture is used internally it promotes sweating and urination, so it may aggravate night sweats and hot flashes.

Acids, Bases and Salts

Many inorganic and organic compounds found in living organisms are ones that we use in our daily lives. They can be classified into one of three group’s acids, bases and salts. Almost all inorganic compounds and many organic compounds can be classified as acids, bases or salts. Acids and bases are strong chemicals and have opposite chemical properties. Acids have a sour taste while bases have bitter taste. When acids and bases react with each other, they form another class of compounds called salts.

Acids – Acids is a substance which produces hydrogen ions when dissolved in water. The word acid has been derived from a Latin word acidus which means sour. It is the hydrogen ions which makes the acid taste sour and turn blue litmus paper red. Hydrogen ions dissociate in aqueous solutions, so an acid will not show its characteristic properties unless water is present.

Bases – These compounds are chemically against acids. Bases have bitter taste. They are also called hydroxides as they have hydroxide group attached. Some bases are soluble in water, they are called alkalis. Alkalies turn red litmus paper blue. Antacid tablets contain magnesium hydroxide and carbonates which can neutralize the excess acid causing indigestion in our stomach.

Salts – Whenever an acid and base are brought together, water is always a product. A negative ion from the acid and a positive ion from a base are always left over. A salt is made up of a positively charged ion called a cation and a negatively charged ion called an anion.

Titration - To determine the Molarity of an Acid or Base

What Is Titration?

Titration is a procedure used in chemistry in order to determine the molarity of an acid or a base. A chemical reaction is set up between a known volume of a solution of unknown concentration and a known volume of a solution with a known concentration. The relative acidity (basicity) of an aqueous solution can be determined using the relative acid (base) equivalents. An acid equivalent is equal to one mole of H⁺ or H₃O⁺ ions. Similarly, a base equivalent is equal to one mole of OH- ions. Keep in mind, some acids and bases are polyprotic, meaning each mole of the acid or base is capable of releasing more than one acid or base equivalent. When the solution of known concentration and the solution of unknown concentration are reacted to the point where the number of acid equivalents equals the number of base equivalents (or vice versa), the equivalence point is reached. The equivalence point of a strong acid or a strong base will occur at pH 7.

For weak acids and bases, the equivalence point need not occur at pH 7. There will be several equivalence points for polyprotic acids and bases.

How to Estimate the Equivalence Point

There are two common methods of estimating the equivalence point:

1. Use a pH Meter

For this method, a graph is made plotting the pH of the solution as a function of the volume of added titrant.
    
2. Use an Indicator

This method relies on observing a color change in the solution. Indicators are weak organic acids or bases that are different colors in their dissociated and undissociated states. Continue reading..

How To Make Sulfuric Acid at Home?

Sulfuric acid is a useful acid to have on hand for a variety of home chemistry projects. However, it is not easy to obtain. Fortunately, you can make it yourself.

Homemade Sulfuric Acid Materials

Actually, this method starts with diluted sulfuric acid, which you boil to make concentrated sulfuric acid. This is the safest and easiest method of making sulfuric acid at home.

• car battery acid
• glass container
• outdoor source of heat, like a grill

Battery acid, which may be purchased at an automotive supply store, is approximately 35% sulfuric acid. In many cases, this will be strong enough for your activities, but if you need concentrated sulfuric acid, all you need to do is remove the water. The resulting acid will not be as pure as reagent-grade sulfuric acid, so keep this in mind.

Safest Method

If you aren't in a hurry, you can concentrate sulfuric acid by allowing the water to evaporate naturally. This takes several days.

1. Place an open container of sulfuric acid someplace with good circulation, safe from the possibility of a spill.
2. Loosely cover the container to minimize contamination with dust and other particulates. 
3. Wait. The water will evaporate out of the solution, eventually leaving you with concentrated sulfuric acid.

Note that sulfuric acid is highly hygroscopic, so it will retain a certain amount of water. You would need to heat the liquid to drive off the remaining water.

Quickest Method

 

The fastest method to concentrate sulfuric acid is to boil the water out of the acid. This is fast, but requires extreme care. You'll want to do this outdoors so that you won't be exposed to acid fumes, using borosilicate glass (e.g., Pyrex or Kimax). There is always a risk of shattering a glass container, no matter what you are heating, so you need to be prepared for that possibility. Do not leave this project unattended!

1. Heat the battery acid in a borosilicate glass pan.

2. When the liquid level stops dropping, you will have concentrated the acid as much as you can. At this point, the steam will be replaced by white vapor, too. Be careful to avoid inhaling the fumes. Continue reading..

Chemical Dynamics of Water Pollution

Chemistry has a long history – is it now time to turn our attention to repairing the damage chemical pollution has inflicted on the environment?

The origins of today’s scientific chemistry date to the turn of the 18th century from experimentation on water, combustion, medicine, and the study of heat.

With the experiments of Joseph Priestly, Antoine Lavoisier, Joseph Black, and Robert Boyle, modern-day chemists learned to understand the differences between alchemy and physical science.

Early Chemists

Although modern chemistry is a relatively new undertaking, the basis of chemistry lies within the origins of civilization. Although some recall the alchemists as early chemists, Alchemy originated from shamanic practices–inspiring their art with mysticism.

The first chemists were pragmatists–their discoveries came from necessity. The original science came from the hunter-gatherers who foraged for grubs, berries and discovered properties of the bark of the Willow tree (a source of primitive aspirin).

Other propitious discoveries included utilizing the foxglove plant for angina and the carrot for pigmentation. Moreover, several thousands of years later, primitive metallurgists utilized iron and bronze for plowing the earth and for weapons. Thus, between then and now, the science of chemistry grew to be appreciated and respected.

From soaps and diabetes medications to paints and gasoline, chemistry made our lives better and simpler.

The Dual-Edged Sword of Chemistry

Many lives have been saved, and riches have been amassed from the modern science of chemistry. However, many lives have also been ruined, and our world’s ecosystem is imperiled from a reckless use of chemistry.

Sadly, we have been poor stewards of the bigger picture. Every day, large volumes of chemicals pollute the  water. The sheer volume appears unimaginable, but it has initiated changes in the biosphere.

Organic chemicals include oil spills, agricultural runoff, and litter ranging from plastic bags to automobile tires.

Inorganic chemicals include litter, smoke and ash from coal-powered plants, and toxic metals (Cobalt, Arsenic, Antimony, Tin and Nickel).

This is the dual-edged sword of chemistry–it is a human aspect. Continue reading..

What is the Purpose of Chromatography?

Finding, isolating, and characterizing medicines derived from nature is a major sub-discipline within chemistry. One often-used technique for isolating potential medicinals is called chromatography – this is a process that separates similar molecules in a mixture.

Early methods separated molecules by color, so scientists called the process, ‘chromatography.’ How is this technique useful?

Chromatography Uses: Drugs From Food

An instance of a potential ‘drug’ isolated from food came from red wine in the 1990s. The substance known as resveratrol gained widespread acclaim as the possible ‘drug.’

Resveratrol was a part of the French paradox — how can people ingest rich, high calorie foods accompanied with a hearty Bordeaux or Pinot Noir wine without increasing their risk of a heart attack or stroke?

The paradox puzzled researchers, and identifying resveratrol as a preventative agent for heart disease was a stroke of scientific genius.

Resveratrol and chemically-similar compounds occur in wine grapes and are classified as phenolic stilbenes, substances which result from plant biochemistry. The eventual isolation of resveratrol via chromatography resulted in isolating other similar molecules of importance.

What are Phenolic Stilbenes–or Polyphenols?

The term stilbene originates from the german, stilbein~ to phosphoresce. The original discovery of the ‘stilbene class’ of molecules came in the late 1800s and was named as such because the molecule possessed a peculiar glow. Presently, theoreticians regard the molecule as rather mundane, except for the biochemical properties that were discovered in the mid-1990s. Continue reading..

How to Find Mass from Mole Fraction?

Mole fraction is simply the moles of a particular substance divided by the total number of moles present. Mole percent is mole fraction times 100. Similar to mole fraction, the mass fraction is nothing more than the mass of the substance divided by the total mass of all substances present. Although the mass fraction is what is intended to be expressed, ordinary usage employs the term mass fraction as well.

Mass (weight) fraction = mass (weight) of A / total mass (weight).

The term mass fraction and mole fraction are dimensionless. Mass percent is the amount of solute in grams present in 100g of the solution. Mole fraction is the ration of number of moles of a particular component to the total number of moles of the solution.

Let’s solve a problem based on mass and mole fraction.

Problem:

Consider 10mg of deprenyl is diluted in 10ml water. Water has the density of 1.0 g/ml. Calculate the mass fraction of the drug.

Solution:

To find the mass fraction first find the total mass of the solution, which is mass of water plus the mass of deprenyl.

m_{water} = (1.0g/mL) (10 mL) = 10g

Note that mass of the drug is negligible compared to the mass of water.

m_{total} = m_{water} + m_{drug} ~  m_{water}

The mass fraction of the drug is,

W_{drug} = m_{drug} / m_{water} = (10 mg/10g) (1g/1000mg) = 1.0 x 10^{-3}.

Examples of Endothermic Reactions

Endothermic reactions absorb heat energy from the surroundings. So that the temperature of the surroundings decreases. In endothermic reaction, the products formed are at a higher energy level than that of the reactants; hence energy is absorbed by the reactants from the surroundings.

Photosynthesis is an endothermic reaction.

 

In endothermic reactions, more energy is required to break bonds than is required to make bonds. Energy is absorbed and the surroundings get cooler. Sometimes you may see sportsman and women putting cold packs on injured ankles, knees or other parts of their bodies. One types of cold packs uses an endothermic reaction to work. The cold packs contains water and ammonium nitrate. As the ammonium nitrate dissolves in water an endothermic reaction takes place and the ice pack becomes very cold.

Some of the examples of endothermic reaction are given below:

1. Decomposition of compounds such as calcium carbonate, copper (II) carbonate, sodium nitrate etc.
2. Food being cooked.
3. Photosynthesis where green plants absorb light energy to make starch.
4. Dissolution of ionic salts like ammonium chloride, ammonium nitrate and sodium carbonate crystals in water.
5. Taking a photograph with a film, light energy is absorbed to decompose the silver bromide on the film to silver and bromine.

Endothermic reactions are less common than exothermic reaction, but there are a number which are quite familiar. For example, when certain salts such as potassium chloride and ammonium nitrate dissolve in water they take in heat from the surroundings and the temperature of the solution drops.
 

Subscripts and Superscripts in Chemistry

Subscript and superscript can make all the difference when it comes to chemical formulas.

Molecules, compounds, and other chemical structures include more than one atom. Sometimes, there are multiples of one particular atom. For instance, anhydrous aluminum chloride features one atom of aluminum joined to or combined with three atoms of chlorine. Its chemical formula reflects this: AlCl₃. But – simply knowing how to use a number in this instance is not enough. It is essential to know the proper use of subscripts and superscripts.

Subscripts in Chemistry

Notice the number 3 is written as a subscript, or a number that is smaller than the other text, and below the normal text line, in the formula for anhydrous aluminum chloride above. The concept of a multiplicity of atoms is conveyed by this use of a subscript.

You can also write the formula for Sucrose or table sugar, using chemical symbols and subscript numbers. There are 12 carbon atoms, 22 hydrogen atoms, and 11 oxygen atoms in sucrose – the chemical formula for table sugar looks like this: C₁₂H₂₂O₁₁.

Sometimes parentheses are used to characterize a particular structure, as follows: (CH₃)₃CCOOH

The above molecule is pivalic acid. We occasionally refer to this molecule as trimethylacetic acid, since, visually, the molecule contains 3 methyl groups CH_3-. Written in its most elemental form, the formula for pivalic acid is C₅H₁₀O₂.

Another more complex structure – acetone, or dimethyl ketone – exemplifies the beneficial use of parentheses.

CH₃(CO)CH₃

How are the parentheses beneficial? In this instance, it is because the oxygen atom is not connected to either the leftmost or the rightmost carbon atom but only the middle carbon atom. Acetone’s chemical structure could also be written (CH₃)₂CO or (CH₃)₂C=O.

 

Superscripts in Chemistry

Atoms often occur as combinations of isotopes. Hydrogen, the simplest gaseous element, has one electron and one proton in all its atoms. However, a small percentage of hydrogen atoms also have a neutron in the nucleus. This form of hydrogen atom is, naturally, heavier than the hydrogen without a neutron. To distinguish them, a superscript is employed. The letter H with a left-justified superscript symbol 1, written ¹H, represents hydrogen containing one nucleon – that is one nuclear particle – a lone proton. Continue reading..

Hydrogenation of Benzene

Benzene hydrogenation is a major petrochemical process. Benzene is readily hydrogenated to cyclohexane using nickel or platinum in fixed beds. Most of the cyclohexane nearly 98% is produced by benzene hydrogenation process. Generally this reaction is carried out at 160 – 220$^{\circ}$C and 25 – 30 atm. Many catalyst such as Ni/alumina and Ni/Pd are used for the reaction.

Benzene hydrogenation has been chosen as a model aromatic substance. This reaction has also been used as model reaction in heterogeneous catalysis by metals where metal-support interactions are involved and the desired product of benzene hydrogenation – cyclohexane is an important chemical intermediate for the synthesis of nylon-66 and nylon-6.

During hydrogenation of benzene some two important observations are made.

1. Partially hydrogenated benzene derivatives were never found – only reaction ends in the formation of cyclohexane.
2. Cyclohexane was dehydrogenated above 200^oC to give the reverse reaction. At higher temperatures benzene cracked to form methane and carbon.

Benzene must be free from sulfur to avoid poisoning the catalyst although the original short uneconomical catalyst were common. Reaction temperature and exotherm can be controlled by evaporation of the product and dilution of the benzene feed with recycled cyclohexane.

Atomic Interactions - Wavefunctions, Orthogonality, Orbitals, Hybridization, & Bonding

Nobel Prize-winning theoretical chemist Linus Pauling wrote a most famous book in 1939, entitling it, The Nature of the Chemical Bond and the Structure of Molecules and Crystals: An Introduction to Modern Structural Chemistry.

There have been few facets of chemistry of greater importance.

Hybridization

Here, we will discuss basic concepts that we hope will lead our readers to a better understanding of what goes on between atoms. We will consider the bonding between carbon atoms in particular.

Wavefunctions

Quantum mechanics is a mathematical discipline that defines the nature and behavior of tiny particle systems, such as atoms and molecules.

At the atomic and subatomic level, particles and waves share similar properties, each isolated system containing one or more particles is described by a mathematically descriptive equation called a wavefunction.
Operators

In mathematics, numbers can be “operated on” to produce certain results. For instance, 3 and 4 can be operated on by multiplying them with each other, to produce the result, 12. Wavefunctions can be operated on in various ways to produce mathematical results that correspond to physical properties. If two wavefunctions are multiplied together yielding the value zero, the wavefunctions are said to be orthogonal.

Orthogonality

An approximate definition for the word orthogonal is perpendicular – this applies to wavefunctions that are orthogonal – they do not interfere with each other. Thus atomic orbitals are orthogonal – they don’t interfere with each other. Continue reading..