Chemistry Past Questions

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H\(_2\) S\(_{(g)}\) + Cl\(_{2(g)}\) → 2HCl\(_{(g)}\) + S\(_{(g)}\) In the reaction above, the substance that is reduced is

  • A. H\(_2\)S
  • B. S
  • C. HCl
  • D. Cl\(_2\)
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Which of the compounds is composed of Al, Si, O and H?

  • A. Epson salt
  • B. Limestone
  • C. Clay
  • D. Urea
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When large hydrocarbon molecules are heated at high temperature in the presence of a catalyst to give smaller molecules, the process is known as

  • A. disintegration
  • B. polymerization
  • C. cracking
  • D. degradation
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In the removal of water hardness, permutit is regenerated with a strong solution of

  • A. NaOH
  • B. Na\(_3\)SO\(_4\)
  • C. Na\(_3\)CO\(_3\)
  • D. NaCl
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A sample of hard water contains some calcium sulphate and calcium hydrogen carbonate. The total hardness may therefore be removed by

  • A. boiling the water
  • B. adding excess calcium hydroxide
  • C. adding a calculated amount of calcium hydroxide
  • D. adding sodium carbonate
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