Waec Chemistry 2009 Past Questions and Answers

Question 16:

• WAEC 2009

Which of the following molecules is not linear in shape?

A. CO₂
B. O ₂
C. NH₃
D. HCI

Question 17:

• WAEC 2009

The number of particles in one mole of a chemical compound is the

A. Atomic number
B. Avogadro's number
C. Mass number
D. Oxidation number

Question 18:

• WAEC 2009

How many molecules are there in 14 g of nitrogen at s.t.p.? [N = 14, Avogadro's constant = 6.02 x 10²³ mol^-1]

A. 6.02 x 10²³
B. 3.01 x 10²³
C. 8.43 x 10²⁴
D. 1.20 x 10²⁴

Question 19:

• WAEC 2009

Consider the reaction represented by the equation: 2NaHCO₃ → Na₂CO ₃ + H ₂O + CO ₂. What is the mass of sodium trioxocarbonate (lV) produced by the complete decomposition of 33.6 g of sodium hydrogen trioxocarbonate (IV)? [NaHCO₃ = 84, Na₂CO₃ = 106]

A. 10.6 g
B. 16.8 g
C. 21.2 g
D. 42.4 g

Question 20:

• WAEC 2009

What is the percentage by weight of calcium in Ca(OCI)₂? [Ca = 40, Cl = 35.5, O = 16]

A. 28.0%
B. 31.6%
C. 43.8%
D. 44.5%