Chemistry 2001 Waec Past Questions and Answers

Question 46 :

• WAEC 2001

Which of the following substances increases in mass when heated in air?

A. Sodium chloride
B. Lodine crystals
C. Magnesium ribbon
D. Copper (ll) oxide

Question 47 :

• WAEC 2001

Calculate the mass of sodium hydroxide in 5.00 dm³ of a 0.125 mol dm^-3 solution [NaOH = 40 g mol]

A. 0.0156 g
B. 0.625 g
C. 1.00 g
D. 25. 0 g

Question 48 :

• WAEC 2001

Which of the following salt solutions will have a pH greater than 7?

A. NaCl_(aq)
B. Na₂CO_3(aq)
C. Na₂SO_4(aq)
D. NaHSO_4(aq)

Question 49 :

• WAEC 2001

What will happen if more heat is applied to the following system at equilibrium? X_2(g) + 3Y _2(g) ⇌ 2XY_3(g); ∆H =-kJmol ^-1

A. The yield of XY ₃ will decompose
B. More of XY₃ will decompose
C. More of X₂ will react
D. The forward reaction will go to completion

Question 50 :

• WAEC 2001

Equal amounts of marble chips are reacted separately with 100cm³ of hydrochloric acid of different concentrations . if all the marble chips reacted, which of the following remained the same in each case?

A. Average rate of evolution of gas
B. Total mass of gas evolved during the reaction
C. Time taken for the reaction to reach completion
D. Lnitial reaction rates