Waec Chemistry 2017 Past Questions and Answers

Question 26:

• WAEC 2017

The number of atoms present in 2.5moles of a triatomic gas is equivalent to [1mole = \(6.02\times 10^{23}\)]

A. \(2.5\times 10^{23}\)
B. \(1.5\times 10^{23}\)
C. \(1.5\times 10^{24}\)
D. \(2.5\times 10^{24}\)

Question 27:

• WAEC 2017

When Magnesium reacts with oxygen, heat is

A. Absorbed and the reaction is endothermic
B. Evolved and the reaction is endothermic
C. Evolved and the reaction is exothermic
D. Absorbed and the reaction is exothermic

Question 28:

• WAEC 2017

Which of the following gases is not acidic?

A. \(SO_{3}\)
B. \(NO_{2}\)
C. \(Co_{2}\)
D. CO

Question 29:

• WAEC 2017

A hydrocarbon contained 14.3% hydrogen. The empirical formula for the hydrocarbon is [H= 1.0, C= 12.0]

A. \(CH\)
B. \(CH_{2}\)
C. \(CH_{3}\)
D. \(CH_{4}\)

Question 30:

• WAEC 2017

Which of the following statements is NOT a chemical property of an acid?

A. Evolution of ammonia when heated with ammonium salts
B. Evolution of carbon dioxide gas when added to a trioxocarbonate (IV) salt
C. Formation of salt and water with alkalis
D. Formation of salt and hydrogen gas with reactive metals