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 statements is NOT a chemical property of an acid?
Evolution of ammonia when heated with ammonium salts
Evolution of carbon dioxide gas when added to a trioxocarbonate (IV) salt
Formation of salt and water with alkalis
Formation of salt and hydrogen gas with reactive metals
Correct answer is A
Ammonium salts react with bases to release ammonia and not with acids.
Which of the following gases is not acidic?
SO_{3}
NO_{2}
Co_{2}
CO
Correct answer is D
The compound CO is treated as a neutral oxide, though in truth, it is slightly acidic. Regardless of this, within the options supplied, CO is the best option available.
When Magnesium reacts with oxygen, heat is
absorbed and the reaction is endothermic
evolved and the reaction is endothermic
evolved and the reaction is exothermic
absorbed and the reaction is exothermic
Correct answer is C
The Magnesium actually reacts with oxygen in the air, is burnt and produces a bright light. The bright light emits a lot of heat so the reaction is exothermic.
2.5\times 10^{23}
1.5\times 10^{23}
1.5\times 10^{24}
2.5\times 10^{24}
Correct answer is C
1 mole = 6.02 \times 10^{23}
2.5 moles = 6.02 \times 10^{23} \times 2.5
= 15.05 \times 10^{23} = 1.505 \times 10^{24}
\approxeq 1.5 \times 10^{24}