Waec Chemistry 1994 Past Questions and Answers

Question 21:

• WAEC 1994

Mg\(_2\) + 2HCI\(_{(aq)}\) → MgCI\(_{2(g)}\) + H\(_{2(g)}\).
From the equation above what mass of hydrogen would be produced if 12.0 g of magnesium reacted completely with dilute hydrochloric acid? (H = 1, Mg = 24)

A. 1.0g
B. 2.0g
C. 6.0g
D. 12.0g
E. 24.0g

Question 22:

• WAEC 1994

The positive of an element in the Periodic Table is determined by

A. Its density
B. Its atomic radius
C. Its relative atomic mass
D. The number of protons in its atom
E. The number of neutrons in its atom

Question 23:

• WAEC 1994

Which of the following electronic structures belongs to a noble gas?[sup][/sup]

A. 1s²2s²
B. 1s ²2s²2p⁴
C. 1s²2s²2p⁶3s²3p⁶
D. 1s²2s²2p²
E. 1s²2s²2p ⁶3s²3p³

Question 24:

• WAEC 1994

In a chemical reaction, the reacting species possess energy of motion known as

A. Potential energy
B. Free energy
C. Bond energy
D. Kinetic energy
E. Hydration energy

Question 25:

• WAEC 1994

The following compounds will decompose on heating except

A. NaHCO₃
B. K₂CO₃
C. MgCO₃
D. Ca(HCO₃)₂
E. ZnCO₃