General Science Questions and Answers

Answer: D

Sulphuric acid is H₂SO₄ - two hydrogen atoms, one sulphur and four oxygen.

It is a dibasic strong acid and the most produced industrial chemical in the world, used in fertilisers, refining, dyes and batteries. K₂SO₄ and Na₂SO₄ are its salts and SO₂ is an oxide of sulphur.

Answer: C

Nichrome - an alloy of about 80 per cent nickel and 20 per cent chromium - is used for the heating elements of electric heaters, irons and toasters.

It has high resistivity, so it heats strongly for a modest current, and it does not oxidise away at red heat because the chromium forms a protective oxide skin.

Answer: D

Spondylitis is inflammation of the vertebrae of the spinal column, from the Greek spondylos, vertebra.

Ankylosing spondylitis, the best-known form, fuses the vertebrae and stiffens the spine; cervical spondylitis affects the neck.

Answer: C

Ecology is the study of organisms in relation to their environment and to one another.

The word was coined by Ernst Haeckel in 1866 from the Greek oikos, household. It covers populations, communities and ecosystems, and the flow of energy and cycling of matter through them.

Answer: A

Pencil 'lead' is graphite, mixed with clay and fired.

Graphite's carbon atoms lie in flat sheets held together only by weak forces, so the sheets slide off onto the paper as the pencil is drawn across it. More clay in the mixture gives a harder, fainter pencil.

Answer: C

Cobalt oxide gives glass a deep blue colour, which is why it is called cobalt blue.

Other oxides give other colours: copper turquoise, chromium green, manganese purple and iron a bottle green. A very small quantity of cobalt colours a large mass of glass.

Answer: D

Peat still shows recognisable traces of the plants it formed from - leaves, twigs and roots are often visible in it.

It is the first stage of coal formation, with only about 25 to 35 per cent carbon. With increasing pressure and time it becomes lignite, then bituminous coal, then anthracite, and all plant structure is lost.

Answer: C

Glass is not an allotrope of carbon. It is an amorphous solid made chiefly of silicon dioxide.

Diamond, graphite and the fullerenes are all pure carbon in different structural forms, along with graphene, carbon nanotubes and amorphous carbon.

Answer: A

Rayon is chemically cellulose. It is made by dissolving wood pulp and forcing the solution through fine holes into an acid bath, where the cellulose is regenerated as a filament.

Because it comes from a natural polymer rather than being built from small molecules, rayon is called a regenerated fibre rather than a true synthetic.

Answer: D

Nitrification is the conversion of atmospheric or soil nitrogen into compounds plants can use.

Strictly it is the two-step bacterial oxidation of ammonia to nitrite by Nitrosomonas and then to nitrate by Nitrobacter. Nitrate is the form in which most plants take up nitrogen.