Who is the ozone layer KILLER??

Ozone (O₃ layer) presents at stratosphere which is 10-50 kilometers above the ground that we are standing on. Practically, ozone is located at 15-30 kilometers above the Earth. It is a highly reactive molecule that made up of 3 oxygen atoms which is covering the Earth, protecting all the organisms from the harm of ultraviolet B radiation emitted by the sun like a shield. Generally, the radiation mentioned will cause skin cancer and cataracts in human and affecting other organisms as well. So, we should appreciate the present of ozone layer.

However, the ozone layer is depleting rapidly in previous 50 years! People might be asking,” What has happened to the ozone? What causes this to be happened?” The fact is it is because of releasing of pollution gases which contains chlorine and bromine when human’s activities. In addition, the main KILLER is Chlorofluorocarbon (known as CFC) which was invented in the late 1920s and early 1930s, by an American scientist called Thomas Midgley. Generally, it acts as coolants in refrigeration system and air-conditional. Moreover, it acts as solvent in order to clean electric components too and plastic foam, and other use in factories. The chart below shows usage of CFC in USA, which is one of the countries that uses CFC pretty much in the world, within 1978.

Usage of CFC in daily life:

So, how does CFC deplete the ozone layer? After some observations and experiments have been done, scientists discover that when CFC flows to higher position, it will eventually undergo dissociation because of sunlight (which means higher temperature), after that, the chlorine molecules will be separated from CFC and reacts with ozone to form oxygen (O₂). Things are getting worse when they found that one molecule of chlorine is able to react with OVER HUNDRED molecules of O₃!! It is because O atom in the ozone will attack the O atom in ClO when present of sunlight too, which means ClO will be reduced to Cl^- ion, then the process starts all over again!

Those reactions can be simplified to:

a) CFCl₃(CFC) + uv → CFCl₂ + Cl^-

b) Cl^- + O₃ → ClO + O₂

c) ClO + O₃ → 2O₂ + Cl^-

**The reactions (b) and (c) will carry on till over hundred times.

As a result, it is starting to have “ozone holes”. Ozone holes, which first found at Antarctica, allow more ultraviolet B radiation reaches the surface of Earth. Study shows that every 1% of ozone depletion will allow 2% of ultraviolet B radiation enters to Earth. As we know, the ultraviolet B radiation will cause harm to all organisms on Earth. For example, human will get skin cancer easily if the percentage of exposure to ultraviolet radiation increases. Moreover, rates of malaria and other infectious diseases will increase as well too. For environment, the life cycle of plant, as well as food chain of animals, will be affected due to the increase amount of radiation.

Although the disaster of CFC has been discovered and some countries have banned usage of CFC, some industries and factories in some countries are still using it because of the advantageous chemical characteristics of CFC such as low in toxicity, nonflammable, noncorrosive, and nonreactive with other chemical species. In addition, the disaster will still go on at least 50 years if the usage of CFC is totally banned in order to let the environment to re-fix the “ozone holes”.

So, what do you think about when you are reading the content above? Are you in air-conditional room now? Or perhaps you were just taking foods from refrigerator? When you know about the consequences of using CFC, what do you do? Undeniable, most of us ignore it, or don’t care about the consequences. The owners of industries or even government encourage the usage of CFC because of their greediness. They want to get more benefits!! Lastly, who is killing the ozone layer? CFC or human?

Resources:
1. http://www.fraqmd.org/OzoneChemistry.htm
2. http//www.ausetute.com.au/cfcozone.html

Enzymes – The nature catalysts

Nature is the most productive of chemical industries. It turns out billions of tonnes of a vast range of products every year using the simplest of starting materials. The catalysts that make all this possible are enzymes – the biological catalysts. As with inorganic catalysts, enzymes speed up chemical reaction without themselves being used up in the course of the reaction. Enzymes are able to catalyse reactions in aqueous solutions under exceptionally mild conditions of temperature and pH.

Enzymes are very specific, generally catalysing only one particular reaction. Carbonic anhydrase, for instance, is an enzyme in red blood cells that catalyses the reaction:

CO₂ + H₂O → H₂CO₃

This enzyme increases the rate of this reaction up to a million fold, increasing the efficiency of removal of carbon dioxide from our bloodstream. In a cellular environment this specificity is absolutely essential – an enzyme must be able to distinguish one amino acid from another or one nucleotide from another. Thus although enzymes are functioning within the rules that define catalytic activity, they differ from ordinary chemical catalysts in several important respects. The rates of enzyme catalysed reactions are typically increased by factors up to 10¹² times compared to the incatalysed reaction. There are several orders of magnitude greater than those of the corresponding chemically catalysed reaction. Enzyme catalysed reactions occur under relatively mild conditions: temperature below 100˚C, atmospheric pressure, and at pH’s around 7. Enzymes have a vastly more defined specificity with regard to their substrate and products. Enzyme catalysed reactions do not produce side products. The catalytic activities of many enzymes can be varied by the concentrations of substances other than the substrate. The mechanism of these regulatory processes can be complex.

Majority of enzymes are water soluble globular proteins. The complicated folding of the protein chain to form the tertiary structures gives rise to clefts of precise geometric shape on the surface of the enzyme. Locks and keys are complementary structures and this would also explain enzyme specificity. One substrate will fit into the active site, just as only one key fits a lock.

Enzymes, as other catalyst function by providing an alternative reaction pathway that requires lower activation energy (Ea). Thus, more molecular interactions posses sufficient energy to produce products. The overall reaction between enzyme and its substrate can be represented by the following equation:

ENZYME (LOCK) + SUBSTRATE (KEY) ↔ ENZYME – SUBSTRATE (KEY IN LOCK) → ENZYME + PRODUCTS

The first stage of the reaction is reversible since if that available energy is not greater than Ea the complex may dissociate without product being formed. In some cases the second stage is also reversible, making the whole enzyme catalysed process capable of proceeding in either direction depending on the cells metabolic requirements. Once the products have been formed, they leave the active site of the enzyme. The enzyme is then free to combine with a new substrate molecule. Enzymes like inorganic catalysts, are not used up in the reaction they catalyst so they can be used again and again.

The youtube video about enzyme in our daily life.

For more informations, visit http//www.rsc.org/education/teachers/learnnet/cfb/enzymes.htm

Effect of caffeine in our daily lives.

Caffeine is an alkaloid; nitrogen containing molecule has a slightly bitter taste and are physiologically active. It’s a mild stimulant having a strong effect on the central nervous system; it is found in food products, consumption of caffeine in coffee, tea, several soft drinks, cocoa, drugs, chocolates and other natural foods. Chemical name 1, 3, 7-trimethylxanthine.

Intake of caffeine into the body is quickly absorbed into the bloodstream and assimilated into the system, is a mild stimulant to the central nervous system, works by binding to a selectively neurotransmitter receptors site on the nerve cells, producing a continual signal, these effects are responsible for the effects of caffeine consumption.

In large quantities, caffeine can cause undesirable side effects such as irregular heartbeat, excess stomach acid, nervousness, headaches, heart burns, high blood pressure and blood sugar level. Also, it can produce birth defects when pregnant woman ingests caffeine; the foetus is exposed and more effected by the drug because of its smaller size.

The consumption or ingest rate of caffeine is sometimes not to the best of our knowledge, whether you drink coffee or not must of us put caffeine in our body , some do it because of energy rush, staying awake to study, whether we eat or drink the effect is still same. Caffeine causes blood vessels in the brain to tighten meaning; less oxygen gets into the blood stream, reason why you can’t a good night sleep if you drink coffee at night because caffeine blocks what is needed to have a deep sleep.

Caffeine has a lot of effect, increasing dopamine levels by exciting parts of your brain that controls pleasure and helps the drug become addictive. Have you ever thought that mountain dew has more caffeine content than it has in coca-cola, while caffeine level in coca-cola has more than in Pepsi in which most of us consume these products on a daily basis without knowing the effects on our health? I personally have never learned this much about caffeine, sure it’s a thing you want to stay awake at night studying, watching movies.

In as much as caffeine has its side effects it also has its health benefits, drinking coffee contains no calories, no fat and barely any carbohydrates; reduces risk of getting cancer, developing skin cancer; used for the treatment of migraine headaches because of its constricted dilated blood vessels; also relieves asthma attacks by widening bronchial airway.

Typical withdrawal symptoms associated with caffeine users even in normal caffeine use is very small meaning only one of coffee. Symptoms are commonly headaches, fatigue, irritability and muscle pain, these symptoms can occur within 24 hrs after the last dose of caffeine. But can be so severe as to cause distress or impairment.

A survey shows that more than 80% of adults consume caffeine on a daily basis; women metabolize caffeine about 25% faster than men do.



Resource: http://www.medicinenet.com/caffeine/article.htm


Structural formula of caffeine.


Some examples of caffeine drinks.

Coca Cola soft drinks



coffee beans



coffee



Energy drinks

Soap

What is soap? How is soap made?

Generally, soap is a surfactant which is used in daily life for cleaning or washing away the dirt. The soap is produced through a process called saponification. Saponification is a chemical process where the sodium hydroxide or potassium hydroxide is used to mixed with the animal fat or vegetablee oil to produced soap and glycerol. In other word, saponification is a process of mixing the fatty acids, either is animal fats or vegetable oils with the alkaline solution or lye to produce the soap (alkali salt with fatty acid) and glycerol. The picture below has illustrated the equation on how the soap is formed:

How is soap function?

Since that most of the dirt are grease and oil, they are unable to dissolve in the water. Thus, here comes the role of soap which act as an emulsify agent to dissolve and wash away the grease and oil along with the water. Do you see people washing something using soap without water? Soap cannot play with single role, hence it must have the water in order to reveal its true function. Well, the unique structure of the soap has plays the main role of dissolving the grease and oils. A soap molecule is made up of both hydrophilic head and hydrophobic tail. Hydrophilic head is able to dissolve the polar molecules, such as water while the hydrophobic tail is able to dissolve the non-polar molecules, such as the oils.

The diagram below shows the structure of the soap molecule:

Due to the unique structure, the soap molecule will form a circular-liked shape, which is also known as the micelles. So how do the micelles form? As I mentioned before, we are washing with both the water and soap, which means that the water molecule are presence surrounding the grease. So, the micelles is formed when the hydrophilic heads of the soap molecules are attracted to the water molecules while the hydrophobic tails of the soap molecules are attracted to the grease. Therefore, the hydrophilic heads will face outward with the water molecules while the hydrophobic tails will face inward with the grease. As a result, it formed the micelles whereby the grease is trapped inside of it and will be washed away by the water as shown the the diagram below.

Advantages and disadvantages of soap

There are few advantages and disadvantages of soap. The advantages of soap are:

1. It is the cheapest among the other surfactants.


2. It is biodegradable since it is made of natural fats and oils.


3. It will not cause any water pollution.


4. Some anti-bacterial soap can remove the bacteria and excessive microflora on the skin to maintain skin health.

Meanwhile, some disadvantages of soap are:

1. It might not as efficiency as other surfactants in removing the dirt.


2. It might remove the natural oils in our skin as well.


3. It will also damage the fabric of clothes.


4. It will form percipitate or scum if react with the lime in hard water, which is the water that contain high mineral ions such as calcium and magnesium ions.


5. It will also damage the proteins in our hair.

Should use or should not use the soap?

There are some tips of using the soap, either you should use or should not use, which are:

1. Use the soap which has additional oil in order to replace the natural oil that had lost on your skin.


2. Use the soap which has the anti-bacterial properties so that it can kill the bacteria on your skin.


3. Use detergent instead of soap to wash your dishes because detergent is more effective in cleaning and removing the dirt on your dishes.


4. Use detergent instead of soap when washing in hard water because detergent will not form any percipitate or scum in hard water.
   
5. Use washing powder instead of soap to wash your clothes because the soap will damage the fabric of your clothes.


6. Use shampoo instead of soap to wash your hair since the soap will damage the protein in your hair.
   
   

For more information, please visit the following sites:

1. http://www.squidoo.com/ChemistryOfDailyLife


2. http://homepages.ius.edu/DSPURLOC/c122/soap.htm


3. http://illumin.usc.edu/article.php?articleID=168


4. http://www.ehow.com/how-does_4913583_soap-clean-hands.html

Chemical Changes in Food Spoilage

Food waste is any food material whether it is raw or cooked is discarded intentionally or unintentionally. In my opinion, food wastage was an irresponsible human act because food discarding may cause our beautiful earth to suffer air pollution. The food waste has causes the releasing of methane gas through the herbaceous digestion process, this may cause the production of methane gas in the earth increases by time and resulting air pollution. In a year, the Americans waste about 100 billion pound of food and approximately 1.5 pounds of food is waste by each of us in our daily life. Have you ever consider about why food is wasted? And what causes the food spoilage?

The food is said to be blemished when it is unhealthy for human health. For vegetables and some fruits, it changes its colour to brown when it contacts with oxygen. In the presence of oxygen, the polyphenal oxidize enzyme which also referred as phenoloxidase, phenolare, monophenol oxidase, diphenol and tyrosinase in chloroplast of plant cells will oxidize the phenolic chemical to o-quinones. There chemicals work together with amino acids from proteins or the chemicals work on itself to create brown polymers. At this stage, the vegetables and fruits are said to be spoiled.

Meat is spoiled by sort of factors but the ordinary cause of meat spoilage is caused by micro-organisms. The factors affecting the growth of the micro-organisms is temperature, osmotic pressure, PH value and oxidation-reduction potential. As temperature increase, the growth rate of the microbial increase too. The microbial attack the glucose and amino acids in the meat therefore results meat spoilage. Sometimes salt is added to inhibits the deterioration action of the microbial because the sodium ions (Na⁺) has an effect on inhibits the action on certain micro-organism. However the micro-organism which resistant to high salt concentration have an ability to lower down the nitrate and nitrite concentration through its metabolisms with the production of nitrous oxide. The nitrate which found in the curing brine is reduced to nitrite and further into nitric oxide through the microbial action. The nitric oxide can reacts with the myoglobin in meat resulting colour fixation. As the salt concentration increases, the concentration of nitrite and nitrate decreases through the enzymes activity found in tissue and without the present of micro-organisms. Salt may inactive certain bacteria that cause the discoloration of meat and some particular salt may stimulate proteolytic anaerobes and preventing meat from curing.

Amount of lactic acid which produced from glycogen during the anaerobic glycolysis process is used to determine the port-mortem pH of meat. Most bacteria grow at approximately pH7 and not well at too acidic or too alkali condition. When muscle is death, the pH value of the muscle will increases due to the lack of the glucose level in muscle. At low glucose level condition, the micro-organisms tend to attack amino acids and causing spoilage to the meat, such as bad odor and discolouration. Besides that, pH determines the amount of the nitrite which present as un-dissociated nitrous acid and inhibits the growth of bacterial. Nitrite also plays an important role in stability of cooked and uncooked cured meats. It lowers the salt concentration which required stabilizing the meat. At the pH range 5.5 to 6.8, the raises of concentration of nitrite, salt, isoascorbate or nitrate in the medium and increase in heat may decrease the manufacture of toxin by the organism. Even though polyphosphate in meat may increase the toxin production, but it uplifts the action of isoascorbate in decreasing toxin production at the same time.

Oxidation-reduction potential is one of the meat spoilage factors. The oxidation-reduction potential (E_h) change accordingly to the myoglobin content, enzymatic activity in the muscle of the organisms and time post-mortem. The E_h delay the initial log phase on microbial growth, so that the eventual growth rate is not affected. The E_h in meat is also affected by the oxygen level and the concentration of molecules which have a marked electropositive character. Cured meats apply an indirect antibacterial effect through raising the E_h of the system in the present of nitrate. At low PH anaerobic condition, nitrate protects bacteria against nitrite.

The youtube video about the change of fresh apple to rotted apple.

For more information, please log on to http://www.mahalo.com/meat-spoilage