Waec Chemistry 1989 Past Questions and Answers

Question 26:

• WAEC 1989

Given that for the reaction. N2(g) + 3H2(g) ⇌ 2NH3(g) ∆H = -92kJ. What is the enthalpy of formation of ammonia from its elements?

A. -46KJ mol ^-1
B. -184KJmol ^-1
C. -92KJmol ^-1
D. 184KJmol ^-1
E. +46KJmol ^-1

Question 27:

• WAEC 1989

The following are s-block elements except

A. Lithium
B. Magnesium
C. Potassium
D. Calcium
E. Aluminium

Question 28:

• WAEC 1989

Which of the following statements is not true of tin? it

A. Is a p-block element
B. Is extracted from cassiterite SnO ₂
C. Is used for protecting iron containers from corrosion
D. Combines with copper to form the alloy brass
E. Shows two oxidation states, + 2 and + 4 in most of its compounds

Question 29:

• WAEC 1989

What quantity of copper will be deposited by the same quantity of electricity that deposited 9.0g of aluminum? (A = 27, Cu = 64)

A. 64g
B. 32g
C. 7.1g
D. 6.4g
E. 3.2g

Question 30:

• WAEC 1989

The electronic configuration of two atoms X and Y are as follows: X - 1s ² 2s ²2p ⁶3s ¹, Y -1s ²2s ²2p ⁶3s²3p ⁶4s ² which of the statements below is true of the position of X and Y in the Periodic Table?

A. X belongs to group 1, Y belongs to period 2,
B. X belongs to group 1, Y belongs to period 4
C. X belongs to group 2, Y belongs to period 1
D. X belongs to group 3, Y belongs to period 2
E. X belongs to group 3, Y belongs to period 4