Learn more about the properties, composition, and structure of substances (elements and compounds) with these Chemistry questions and answers. This Test can be used by students preparing for Chemistry in JAMB, WAEC, NECO or Post UTME.
Which of the following organic compounds can undergo both addition and substitution reactions?
Pentane
Benzene
Propane
Hexane
Correct answer is B
An example of benzene addition reaction is the formation of cyclohexane by a mix of benzene vapour and hydrogen passed over nickel catalyst; while chlorobenzene is formed by substitution reaction.
Which of the following raw materials is used in the plastic industry?
Ethene
Methane
Sulphur
Hydrogen
Correct answer is A
Ethene is the most important organic chemical, by weight, that is manufactured. It is an important raw material for the production of plastics and antifreeze solutions as well as solvents.
be very reactive and will attack ozone
be non-reactive and will not attack ozone
not change the level of ozone in the atmosphere
increase the level of ozone in the atmosphere
Correct answer is A
CFCs (Chlorofluorocarbons) have a lifetime in the atmosphere of about 20 to 100 years, and consequently one free chlorine atom from a CFC molecule can do a lot of damage, destroying ozone molecules for a long time
Which of the following separation techniques can be employed in obtaining solvent from its solution?
Evaporation
Distillation
Filtration
Precipitation
Correct answer is B
Distillation is the process of separating the components or substances from a liquid mixture by using selective boiling and condensation.
boiling the water
adding excess calcium hydroxide
adding a calculated amount of calcium hydroxide
adding sodium carbonate
Correct answer is D
Its D because when sodium carbonate reacts with calcium hydrogentrioxocarbonate it gives sodium hydrogentrioxocarbonate and calcium trioxocarbonate. However, when it react with calcium sulphate, calcium carbonate and sodium tetraoxosulphate is formed