Chemistry Past Questions And Answers
Sodium hydroxide solution can be conveniently stored in a container made of?
- A. lead
- B. zinc
- C. aluminium
- D. copper
Which of the following when heated strongly in air will leave a metal as residue?
- A. Sodium trioxonitrate (V)
- B. Potassium trioxonitrate (V)
- C. Silver trioxonitrate (V)
- D. Lead (ll) trrioxonitrate(V)
NH3(g) + HCl(g) → NH4Cl(s) The entropy change in the system above is
- A. negative
- B. indeterminate
- C. positive
- D. zero
(a) Explain the statement, the standard electrode potential of zinc is -0.76 v.What is meant by the termperiodic property of elements?
(b) Consider the following standard electrode potentials:
Zn\(^{2+}\)\(_{(aq)}\) + 2e\(^-\) Zn(s) E? = - 0.76 V
Cu\({2+}\)\(_{(aq)}\) + 2e\(^-\) Cu(s) E? = + 0.34 V
When thetwo half cells are connected:
(i) write the reaction equation at each electrode;
(ii) write the overall cell reaction equation;
(iii) state the type of reaction occurring at each electrode;
(iv) calculate the e.m.f. of the cell.
(c) (i) Nametwo chemical industries.
(ii) Statetwo factors that should be considered when siting a chemical industry.
(iii) List two effects of a chemical industry on the community in which it is sited.
(d) Using chemical equations, explainbriefly what would happen when hydrogen peroxide is added to:
(i) silver oxide;
(ii) chlorine gas.
(e) List three physical properties of nitrogen.
View Discussion (0)WAEC 2018 THEORY(a) (i) Define standard electrode potential.
(ii) State two factors that affect the value of standard electrode potential.
(iii) Give two uses of the values of standard electrode potential.
(iv) Draw and label a diagram for an electrochemic cell made up of Cu\(^{2+}\)/Cu; E° = +0.34 V Zn\(^{2+}\)/Zn; E° = -0.76 V
(v) Calculate the e.m.f. of the cell in (a)(iv) above.
(b) (i) In terms of electron transfer, define: I. oxidation; II. oxidizing agent.
(ii) Balance the following redox reaction: MnO\(^{-4}\) + l\(^{-}\) \(\to\) l\(_{2}\) + Mn\(^{2+}\)
(c) Classiify each of the following oxides as basic, amphoteric, acidic or neutral: (i) Carbon (II) oxide; (ii) Sulphu (IV) oxide; (iii) Aluminium oxide; (iv) Lithium oxide.
(d) What is hydrogen bonding?
View Discussion (0)WAEC 2012 THEORYThe following are uses of sulphur except
- A. manufacture of tetraoxosulphate (VI) acid
- B. prevention of the growth of fungi
- C. vulcanization of rubber
- D. coating of steel to prevent rusting
Which of the following pairs of compounds belongs to the same homologous series?
- A. C3H8 and C3H6
- B. C4H10 and C5H10
- C. C2H4 and C4H10
- D. C2H6 and C4H10
(a) List two products obtained when crude oil is refined
(b)(i) What is the general formula for alkanols?
(ii) State the type of reaction involved in the conversion of ethanol to ethanoic acid
(iii) Write an equation to show how ethanoic acid reacts with sodium trioxocarbonate (IV).
View Discussion (0)WAEC 1997 THEORYThe following are uses of sulphur except
- A) vulcanization of rubber
- B) manufacture of dyes
- C) coating of steel to prevent rusting
- D) manufacture of tetraoxosulphate (VI) acid
The spreading of the scent of a flower in a garden is an example of?
- A. Brownian motion
- B. Diffusion
- C. Osmosis
- D. Tynadal effect