Chemistry Past Questions And Answers
Which of the following arrangements indicates the correct decreasing order of ionization energy of period 3 elements?
- A. Na, Al, P, Cl
- B. Cl, P, Al, Na
- C. Na, P, Cl, Al
- D. Al, Na, P, Cl
(a) (i) Listtwo gaseous pollutants that can be generated by burning coal.
(ii) Explain briefly why coal burns more easily when it is brokeninto pieces than when it is in lumps.
(iii What gas is responsible formost of the explosions in coal mines?
(iv) Name the non-volatile residue left behind after the destructive distillation of coal.
(b) Stateone oxide ineach case which:
(i) is used in bleaching;
(ii) oxidizes hot concentrated HCl to chlorine;
(iii) dissolves in water to give a solution withpH greater than 7;
(iv) reacts with NaOH and also with HCl;
(v) is a reddish-brown gas.
(c) (i) Write a balanced chemical equation for the reaction between chlorine gas and iron(II) chloride solution.
(ii) State the type of reaction in(c)(i).
(iii) Give a reason for your answer in(c)(ii).
(d) Consider the following set-up:
(i) IdentifyA andB.
(ii) Write a balanced chemical equation for the reaction.
(iii) Name the gas produced.
(iv) Why was the flask tilted downwards?
(v) What is the:
(I) function of B in the experiment;
(II) method of collection of the gas?
(e) Giveone product obtained from refining petroleum that is solid.
In the purification of town water supply, alum is used principally to
- A) kill bacteria
- B) control the pH of water
- C) improve the taste of the water
- D) coagulate small particles of mud
Which of the following substances is not a homogenous mixture?
- A) filtered sea water
- B) soft drink
- C) flood water
- D) writing ink
Chlorine is is used in water treatment as
- A. a germicide
- B. a decolorizing agent
- C. an antioxidant
- D. a coagulating agent
Which of the following compounds will undergo additional reactions?
- A) Ethyne
- B) Butane
- C) Petane
- D) Ethanol
Which of the following acts as both reducing and oxidized agent?
- A. H2
- B. SO2
- C. H2S
- D. CO2
NH3(g) + HCl(s) → NH4Cl(s) The entropy change in the system above is
- A) positive
- B) zero
- C) negative
- D) indeterminate
Which of the following species correctly represented an ion of M with 13 protons and 10 electrons?
- A.10M3+
- B.10M3-
- C.13M3+
- D.13M3-
Zinc oxide is said to be amphoteric because it
- A. forms an acid salt
- B. is an insoluble base
- C. forms a double salt
- D. reacts with a base or an acid