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2 marksThe Atmosphere

CAPE Chemistry Unit 2 · May/June 2023 · Paper 2 · Question 3(b)(ii)

CCl₄ is an effective fire extinguisher but is no longer used due to its toxicity and role in ozone depletion. In the upper atmosphere, a bond in CCl₄ breaks, forming reactive species.

The reactive species formed from CCl₄ act as catalysts in the decomposition of ozone. Write TWO equations to show how EACH of these species acts as catalysts.

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Other parts of this question

  1. 3(a)(i)Write half-equations to represent the reactions taking place at the anode and cathode in the diaphragm cell.[2 marks]
  2. 3(a)(ii)Deduce ONE reason why the anode in the diaphragm cell is NOT made of steel.[1 mark]
  3. 3(a)(iii)Discuss TWO environmental concerns associated with EACH of the following: The production of chlorine using the diaphragm cell; The manufacture or use of PVC or…[4 marks]
  4. 3(b)(i)Identify the condition that causes a bond in CCl₄ to break in the upper atmosphere. Deduce an equation for the formation of the reactive species.[2 marks]
  5. 3(b)(iii)State the name given to this upper atmosphere.[1 mark]
  6. 3(b)(iv)Discuss the importance of the ozone layer to all life on planet earth.[2 marks]
  7. 3(c)(i)Identify the components labelled A, B, C, D and E in Figure 1.[5 marks]
  8. 3(c)(ii)Explain how this initiative will help maintain levels of oxygen and carbon dioxide in the atmosphere.[3 marks]
  9. 3(d)(i)Define EACH of the following terms: Reuse, Reduce, Recycle.[3 marks]
  10. 3(d)(ii)Complete the table below outlining simple laboratory tests that would confirm the presence of Pb²⁺ and NO₃⁻.[4 marks]

More practice: the rest of this paper · more The Atmosphere questions · all CAPE Chemistry Unit 2 past papers