Waec Chemistry Past Questions For Year 1988
Question 31
Which of the following correctly explains why iodine crystals change directly into the gaseous state when heated?
- A. lodine crystals sublime
- B. lodine atoms are held together by strong forces
- C. lodine molecules are held together by weak forces
- D. lodine molecules are covalent
- E. lodine is a solid at room temperature
Question 32
Aqueous sodium trioxocarbonate (IV) solution is alkaline because
- A. acid from which it is formed is strong
- B. sodium is an alkali metal
- C. sodium trioxocarbonate (IV) is decomposed by water
- D. sodium trioxocarbonate (lV) is stable to heat
- E. sodium triocarbonate (IV) is hydrolysed in water
Question 33
During the electrolysis of dilute tetraoxosulphate (VI) acid solution 0.05 mole of electrons were passed what volume of gas was produced at the anode? (Gaseous molar volume = 22. 4dm3 at s.t.p)
- A. 0.224 dm3
- B. 0.280 dm3
- C. 0.560 dm3
- D. 2.24 dm3
- E. 22.4 dm3
Question 34
The reaction represented by the equation C(s) + H2O(l) → CO(s) + H 2(s) was carried out at 27oC if the enthalpy change was + 4500 J and the entropy change was + 12J, what was the free energy change? (∆G = ∆H - T∆S)
- A. - 4176 J
- B. +4176 J
- C. - 900 J
- D. + 900 J
- E. +8100 J
