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 is used to power steam engines?
lubricating oil
coal
bitumen
diesel oil
Correct answer is B
When we burn coal on a fire, the bonds break apart and the energy is released in the form of heat. Coal contains about half as much energy per kilogram as cleaner fossil fuels such as gasoline, diesel, and kerosene—and that's one reason why steam engines have to burn so much of it.
Coal is the fuel used to power steam engines.
2KClO\(_3\)(s) → 2KCl(s) + 3O\(_2\)(g)
The importance of the catalyst in the reaction above is that
heating may not be required before the reaction takes place
the reaction is controllable even at a high temperature
the reaction produces large quantity of oxygen
the reaction takes place more rapidly at a lower temperature
Correct answer is D
A catalyst is a substance that enables a chemical reaction to proceed at a usually faster rate or under different conditions (as at a lower temperature) than otherwise possible.
the density of oxygen is greater than that of air
the density of air is nearly the same as that of oxygen
oxygen is a component of air
air is an impure substance
Correct answer is B
Oxygen is collected in downward displacement of water because:-
nitrogen and carbondioxide
the rare gases
nitrogen and oxygen
nitrogen and the rare gases
Correct answer is D
The quick-lime is a drying agent that can dry most gases except ammonia. Hence it removes the water vapour. Quick-lime which is calcium oxide reacts with the carbon dioxide forming calcium carbonate. Hence carbon dioxide and monoxide is eliminated leaving nitrogen, and the rare gases
A balanced chemical equation obeys the law of
conservation of mass
definite proportions
multiple proportions
conservation of energy
Correct answer is A
No explanation has been provided for this answer.