Waec Chemistry 2006 Past Questions and Answers

Question 6:

• WAEC 2006

If 20 cm³ of distilled water is added to 80cm ³ of 0. 50 mol dm^-3 hydrochloric acid, the new concentration of the acid will be

A. 0.10mol dm^-3
B. 0.20mol dm^-3
C. 0.40mol dm^-3
D. 2.00mol dm^-3

Question 7:

• WAEC 2006

Consider the reaction represented by the equation. 2NaHCO_3(s) \(\rightarrow\) 2Na₂CO _3(S) + CO _2(g) + H₂O_(g) what volume of carbon (IV)oxide at s.t.p is evolved when 0. 5 moles of NaHCO₃ is heated? [Molar volume = 22.4 dm³ at s.t. p]

A. 1.12dm³
B. 2.24dm³
C. 5.6dm³
D. 56.0dm³

Question 8:

• WAEC 2006

Considered the reaction: H⁺_(aq) + OH ^-_(aq) → H₂O_(l). The energy change taking place in the reaction above is enthalpy of

A. Formation
B. Hydration
C. Neutralization
D. Solution

Question 9:

• WAEC 2006

Which of the following processes is an endothermic reaction?

A. Dissolving NH₄CI crystals in water
B. Addition of concentrated H₂SO₄
C. Dissolving NaOH pellets in water
D. Passing SO₃ gas into water

Question 10:

• WAEC 2006

Which of the following aqueous methods cannot be used to distinguish between a strong acid and a a weak acid?

A. Conductivity measurement
B. Measurement of pH
C. Measurement of heat of neutralization
D. Action on starch iodide paper