Waec Chemistry 2020 Past Questions and Answers

Question 31:

• WAEC 2020

What volume of oxygen at s.t.p is required to burn completely 7.5 dm\(^3\) of methane according to the following equation?
CH\(_4\) \(_g\) + 20\(_2\) \(_g\) → CO\(_2\) \(_g\) + H\(_2\)O\(_g\)

A. 3.75 dm\(^3\)
B. 7.59 dm\(^3\)
C. 15.0 dm\(^3\)
D. 30.0dm\(^3\)

Question 32:

• WAEC 2020

When 250 cm3 of a saturated solution of CuSO\(_4\) at 30°C was evaporated to dryness, 5.0 g of the salt was obtained..
What is the solubility of the salt at 30°C? [CuSO\(_4\) = 160]

A. 0.031
B. 0.125
C. 0.640
D. 1.560

Question 33:

• WAEC 2020

The bond between NH\(_3\) and H\(^+\) in NH4\(^+\) is?

A. Dative
B. Covalent
C. Hydrogen
D. Electrovalent

Question 34:

• WAEC 2020

Which of the following oxides has a giant covalent structure?

A. Al\(_2\)O\(_3\)
B. Na\(_2\)O
C. P\(_4\)O\(_10\)
D. SiO\(_2\)

Question 35:

• WAEC 2020

Which of the following hydroxides is not readily soluble in water?

A. NH\(_4\)OH
B. Ca(OH)\(_2\)
C. NaOH
D. KOH