Friday, 17 May 2013
Sunday, 12 May 2013
CHEMIST!
Chemist
Learn interesting facts and information about a range of science jobs and careers.
What is a chemist? What do they do as part of their job? Read our job description facts and information to find out the answers to these questions and more while learning all about chemistry careers.
- Chemists study various chemical elements and compounds, their properties and how they work together in our bodies and the world around us.
- Specialist fields in chemistry include biochemistry, organic chemistry, inorganic chemistry, nuclear chemistry, physical chemistry and analytical chemistry.
- Important subjects related to chemistry include physics, English, algebra, calculus and computer science.
- It helps for chemists to have a well rounded science knowledge.
- Good chemists usually have an eye for detail, patience, curiosity and the ability to work on their own.
- Those who study chemistry can find jobs as researchers, laboratory technicians, teachers and other important roles.
- Chemists can be in high demand in industries such as the production of chemicals and pharmaceutical products.
- A bachelor’s degree is sufficient for a number of positions but higher areas of research often require a PhD.
- Famous chemists include Louis Pasteur and Michael Faraday.
Friday, 10 May 2013
ESTERS
NATURAL RUBBER
Natural rubber, also called India rubber or caoutchouc, as initially produced, consists of suitable polymers of the organic compound isoprene with minor impurities of other organic compounds plus water. Forms of polyisoprene that are useful as natural rubbers are classified as elastomers. Currently the rubber is harvested mainly in the form of the latex from certain trees. The latex is a sticky, milky colloid drawn off by making incisions into the bark and collecting the fluid in vessels. This process is called "tapping". The latex then is refined into rubber ready for commercial processing. Natural rubber is used extensively in many applications and products, either alone or in combination with other materials. In most of its useful forms it has a large stretch ratio, high resilience, and is extremely waterproof.
How To Become Excellent Student?
Steps
- 1Like all exceptionally great students, you must pay attention! When a teacher is giving a lesson, take notes and if you don't understand something, raise your hand and ask questions. The more questions you ask, the smarter you'll get, believe it or not. By passing notes and talking to friends, you won't learn anything, so pay close attention!
- 2Review your notes when you have free time.
- 3Take some time to write some problems up, or you could ask someone to write them for you. Just remember, it doesn't hurt to go over what you have learned.
- 4Do your homework. Teachers give you homework for a reason. It is to review what you have learned that day. Take advantage of your free time. Do your homework on the way home from school in any spare time. Do as much at school as you can-there you have the teacher in case you need help. Make sure not to rush on your homework, to check over it, and to be neat. If you really want to be a successful student, you should know right from the beginning when you want to be great at anything, you have to put up with things that just don't seem fair. Doing your homework is not a big deal. Remember, homework can also help you develop good habits and attitudes.Always do what is asked of you.
- 5Be prepared. Bring everything you need with you to class. Books, folders, pens, pencils, homework, review sheets etc. whatever you need it would be a good idea to bring it.
- 6Get organized. Staying organized in school is really important. If you are organized, then you are one step ahead in being successful. Keep a folder for each subject, and yes, you put your math papers in your math folder, you put your Language Arts papers in your Language Arts folder, you put your science papers in your science folder, and so on. It would really be a good idea to color code or label your folders.
- 7Study. It would be a good idea to start studying a few days before a test. Make a studyschedule. If an extracurricular activity gets in the way of your studying, tell the person in charge of that certain event, that you will not be able to attend that event, or you will have to leave early. However, there will be certain situations where you will have to attend whatever it is. In this kind of situation, you will just have to study another day. This is where your study schedule comes in. Write out a schedule of the week of your test and find your free time. Always remember, use your time wisely. Study as if you are motivated for the outcome of your hard work.
- 8Start to read a little more. If you are not already a reader, start at your level and work your way up. You may not know this, but by reading more challenging and difficult books, you are expanding your vocabulary.
- 9Ask a parent or older sibling to look over your notes and create a mini-test for you 3 days advance of your test. You should always want to study before the night of your test.
- 10If you're stuck then do not lose your cool, just focus on your work and you'll succeed.
- 11Use of mind maps can be helpful for understanding hard topics.
Thursday, 9 May 2013
FATS AND OILS
Fats form a category of lipid, distinguished from other lipids by their chemical structure and physical properties. This category of molecules is important for many forms of life, serving both structural and metabolic functions. They are an important part of the diet of most heterotrophs (including humans). Fats or lipids are broken down in the body by enzymes called lipases produced in the pancreas.
Examples of edible animal fats are lard, fish oil, butter/ghee and whale blubber. They are obtained from fats in the milk and meat, as well as from under the skin, of an animal. Examples of edible plant fats include peanut, soya bean, sunflower, sesame, coconut and olive oils, and cocoa butter. Vegetable shortening, used mainly for baking, and margarine, used in baking and as a spread, can be derived from the above oils by hydrogenation.
These examples of fats can be categorized into saturated fats and unsaturated fats. Unsaturated fats can be further divided into cis fats, which are the most common in nature, and trans fats, which are rare in nature but present in partially hydrogenated vegetable oils.
DOES OIL COMES FROM DINOSOURS?
The notion that petroleum or crude oil comes from dinosaurs is
fiction. Surprised? Oil formed from the remains of marine plants and
animals that lived millions of years ago, even before the dinosaurs. The
tiny organisms fell to the bottom of the sea. Bacterial decomposition
of the plants and animals removed most of the oxygen, nitrogen,
phosphorus and sulfur from the matter, leaving behind a sludge made up
mainly of carbon and hydrogen. As the oxygen was removed from the
detritus, decomposition slowed. Over time the remains became covered by
layers upon layers of sand and silt.
As the depth of the sediment
reached or exceeded 10,000 feet, pressure and heat changed the remaining
compounds into the hydrocarbons and other organic compounds that form
crude oil and natural gas.
The type of petroleum formed by the
plankton layer depended largely on how much pressure and heat were
applied. Low temperatures (caused by lower pressure) resulted in a thick
material, such as asphalt. Higher temperatures produced a lighter
petroleum. Ongoing heat could produce gas, though if the temperature
exceeded 500°F, the organic matter was destroyed and neither oil nor gas
was produced.
Silly Putty
Here is an interesting activities that you can do at home. Silly putty can be made with common household objects, and is a great chemistry experiment to do with starch. Enjoy it!
Application of Carbon in Industries
There are so many uses of carbon in industries. We can conclude that, carbon are very important to our industries. Here, we attached some application of carbon.
Application of Carbon In Daily Life
There are so many thing that applied carbon in our daily life. The most closure to us is pencil. Carbon is used in pencil lead.
If you are wearing a diamond ring that is also carbon.
Also graphite powder is used as a lubricant.
Carbon as a semiconducting material is used in electrical resistors, and spark plug wires. Carbon is added (in specific quantities) to steel to give it a desired hardness.
- Carbon is used as a base for the ink in inkjet printers.
- Carbon, in the form of carbon dioxide, is used in the manufacture of many fizzy and carbonated drinks. It is also used in fire extinguishers.
- Dry ice, which is the solid form of carbon dioxide, is used as a cooling agent.
- Freon, is used in cooling systems and devices like refrigerators and air conditioners.
- Carbon is also used to manufacture many heat resistant devices and tools and metal cutters.
- It is used as a decorative tool in many jewelry items.
- Carbon monoxide, extracted through metallurgical process, is used as a reducing agent to obtain many elements and compounds.
- Vegetal carbon, which is an amorphous form of carbon, is utilized as a bleaching agent and a gas absorbent.
- Carbon is used in the rim of automobiles as a black fume pigment.
- Calcium carbide is used as a welding agent for cutting metals, in the preparation of acetylene and other organic compounds.
Overall Notes
Here are few notes of overall chapter Carbon Compound provided for your references. We are glad to help you my dear students.
Wednesday, 8 May 2013
10 CARBON FACTS
Carbon - The Chemical Basis for Life
By Anne Marie Helmenstine, Ph.D.,
1. Carbon is the basis for organic chemistry, as it occurs in all living organisms.
2. Carbon is a nonmetal that can bond with itself and many other chemical elements, forming nearly ten million compounds.
3. Elemental carbon can take the form of one of the hardest substances (diamond) or one of the softest (graphite).
4. Carbon is made in the interiors of stars, though it was not produced in the Big Bang.
5. Carbon compounds have limitless uses. In its elemental form, diamond is a gemstone and used for drilling/cutting; graphite is used in pencils, as a lubricant, and to protect against rust; while charcoal is used to remove toxins, tastes, and odors. The isotope Carbon-14 is used in radiocarbon dating.
6. Carbon has the highest melting/sublimation point of the elements. The melting point of diamond is ~3550°C, with the sublimation point of carbon around 3800°C.
7. Pure carbon exists free in nature and has been known since prehistoric time.
8. The origin of the name 'carbon' comes from the Latin word carbo, for charcoal. The German and French words for charoal are similar.
9. Pure carbon is considered non-toxic, although inhalation of fine particles, such as soot, can damage lung tissue.
10. Carbon is the fourth most abundant element in the universe (hydrogen, helium, and oxygen are found in higher amounts, by mass).
CARBOXYLIC ACIDS
1. Carboxylic acids are organic compounds which form an homologous series with the general
formula of CnH2n+1COOH.
2. Carboxylic acids are compounds which contain a -COOH functional group.
3. Carboxylic acids are weak acid which ionize partially in water to produce lower concentration of
hydrogen ions compare to strong acid. Ethanoic acid turns moist blue litmus paper red.
CH3COOH <–> CH3COO- + H+
4. Physical properties of carboxylic acid
| Name | Molecularformula | Boiling point (°C) |
| Methanoic acid(Formic acid) | HCOOH | 101 |
| Ethanoic acid(Acetic acid) | CH3COOH | 118 |
| Propanoic acid | C2H5COOH | 141 |
| Butanoic acid | C3H7COH | 164 |
- Solubility in water – generally in carboxylic acid (the less than four carbon atoms) are very soluble in water and ionise partially to form weak .
- Density of carboxylic acid – density of carboxylic acid increases due to the increases in the number of carbon atoms in a molecule.
- Boiling points – all carboxylic acid in general have relatively high boiling points than the corresponding alkanes. This is due to the presence of carboxyl group in carboxylic acid.
- Smell – carboxylic acid (< 10 carbon) are colourless and pungent smell. Carboxylic acid (>10 carbons) are wax-like solids.
| Formula | Common Name | Source | IUPAC Name | ||
|---|---|---|---|---|---|
| HCO2H | formic acid | ants (L. formica) | methanoic acid | ||
| CH3CO2H | acetic acid | vinegar (L. acetum) | ethanoic acid | ||
| CH3CH2CO2H | propionic acid | milk (Gk. protus prion) | propanoic acid | ||
| CH3(CH2)2CO2H | butyric acid | butter (L. butyrum) | butanoic acid | ||
| CH3(CH2)3CO2H | valeric acid | valerian root | pentanoic acid | ||
| CH3(CH2)4CO2H | caproic acid | goats (L. caper) | hexanoic acid | ||
| CH3(CH2)5CO2H | enanthic acid | vines (Gk. oenanthe) | heptanoic acid | ||
| CH3(CH2)6CO2H | caprylic acid | goats (L. caper) | octanoic acid | ||
| CH3(CH2)7CO2H | pelargonic acid | pelargonium (an herb) | nonanoic acid | ||
| CH3(CH2)8CO2H | capric acid | goats (L. caper) | decanoic a |
5. Preparation of carboxylic acid
Oxidation of an alcohol
-
The oxidation of ethanol is used to prepare ethanoic acid.
C2H5OH + 2[O] –> CH3COOH + H2O
Carried out by refluxing* ethanol with an oxidising agent
[acidified potassium dichromate(VI) solution – orange colour turns to green /
acidified potassium manganate(VII) solution – purple colour turns to colourless]
6. Chemical properties of carboxylic acid
- Reaction with metals
- Ethanoic acid reacts with reactive metals (copper and metals below it in the reactivity series cannot react with ethanoic acid).
- (K, Na, Mg, Al, Zn, Fe, Sn, Pb, Cu, Hg, Au)
- Reaction with bases acid neutralises alkalis (sodium hydroxide).
CH3COOH + NaOH –> CH3COONa + H2O
In this reaction, a salt (sodium ethanoate) and water are formed.
- Reaction with carbonates
Ethanoic acid reacts with metal carbonates (calcium carbonate, magnesium carbonate, zinc carbonate).
2CH3COOH + CaCO3 –> Ca(CH3COO)2 + CO2 + H2O
In this reaction, a salt (calcium ethanoate), carbon dioxide and water are formed.
- Reaction with alcohols (Esterification)
Ethanoic acid reacts with alcohol (ethanol, propanol, butanol)
CH3CO-OH + H-OC4H9 –> CH3COOC4H9 + H2O (Concentrated H2SO4 is a catalyst)
In this reaction, an ester (colourless sweet-smelling liquid) (butyl ethanoate) and water are formed.
7. Uses of Carboxylic Acid
 |
| soap |
 |
| vinegar |
| aspirin |
| coagulant |
 |
| dye |
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