What are aromatics?

Q10. What are aromatics?

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.

How is plastic made?

Q9. How is plastic made?

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.

What is cellulose?

Q6. What is cellulose?

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.

How is oil refined?

Q4. How is oil refined?

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.

Who discovered the shape of DNA?

Q2.Who discovered the shape of DNA?

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.