Chemistry 2018 Waec Past Questions and Answers

Question 6 :

• WAEC 2018

What is the solubility of a salt if 0.4g of it is obtained on evaporating 200\(cm^{3}\) of its saturated solution to dryness?

A. 0.08\(gdm^{-3}\)
B. 2.00\(gdm^{-3}\)
C. 8.00\(gdm^{-3}\)
D. 80.00\(gdm^{-3}\)

Question 7 :

• WAEC 2018

An acidic salt has

A. Double anions in its aqueous solution
B. A single cation in its aqueous solution
C. Hydrogen ions in its aqueous solution
D. Hydrogen atoms in its aqueous solution

Question 8 :

• WAEC 2018

A reaction is endothermic if the

A. Reaction vessel feels cool during the reaction
B. Enthalpy change is negative
C. Bond forming energy exceeds bond breaking energy
D. Heat of formation of reactants exceeds heat of formation of products

Question 9 :

• WAEC 2018

In which of the following compounds does hydrogen form ionic compounds?

A. CH\(_{4}\)
B. HCl
C. NH\(_{3}\)
D. NaH

Question 10 :

• WAEC 2018

An organic compound has the empirical formula \(CH_{2}\). If its molar mass is 42\(gmol^{-1}\), what is its molecular formula? (C = 12.0, H = 1.0)

A. \(C_{2}H_{4}\)
B. \(C_{3}H_{4}\)
C. \(C_{3}H_{6}\)
D. \(C_{4}H_{8}\)