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..