Ans. Benezene is a clear liquid organic chemical found in coal tar. It can be harmful, but has many uses, for example as a cleaning fluid and in manufacturing dyes. It has distinctive hexagonal molecules made of six carbon atoms and six hydrogen atoms and called a benezene ring. It also has a distinctive aroma, which is why chemicals that have a benezene rings are called aromatics.
Ans. Carbon atoms often link together like the links of a chain to form very long thin molecules- as in the molecule of propane, which consists of three carbon atoms in a row, with hydrogen atoms attached.
Ans. Most plastics are made from ethene, one of the products of cracked oil. When heated under pressure, the ethene molecules join in chains 30,000 or more long. These molecules get tangled like spaghetti. If the strands are held tightly together, the plastic is stiff. of the strands can slip easily over each other, the plastic is bendy, like polythene.
Ans. Oil is formed from tiny plants and animals that lived in warm seas millions of years ago. As they died, they were slowly buried beneath the sea-bed.AS the sea-bed sediments hardened into rock, the remains of the organisms were turned to oil and squeezed into cavities in the rock.
Ans. Cellulose is a natural fibre, found in the walls of all plant cells. It is polymer, made of long chains of sugar molecules. These long chains make it tough and stringy, which is why we can’t digest it when we eat plants-it passes through our bodies largely intact.
DNA is Deoxyribonucleic Acid. This is the amazing long double-sprial molecule that is found inside every living cell. it is made up of long chains of sugars and phosphates linked by pairs of chemical ‘bases’-adenine, cytosine, guanine and thymine. the order in which these bases recur provides in code Read More …
Ans. Oil drilled from the ground, called crude oil, is separated into different substances, mainly by distillation. This means the crude oil is heated until it evaporates. The substances are then drawn off and condensed from the vapour at different temperatures. The molecules of heavier oils may then be ‘cracked’ by heating under pressure.
Ans. Polymers are substances made from long chains of thousands of small carbon-based molecules, called monomers, strung together. Some ploymers occur naturally, such as wool and cotton, but plastics such as nylon and polythene are man-made polymers.
Ans. The discovery in 1953 that every molecule of DNA is shaped like a twisted rope ladder or ‘double helix’ eas ine of teh great scientific breakthroughs of the 20th century. Maurice Wilkins and Rosalind Franklin did the groundwork for teh discovery. Francis Crik and James Watson, two young reasearchers at Cambridge University, UK, had the inspiration and won the Nobel Prize.