Question 4
(4) In the mid-1980s, scientists discovered a hole in the ozone layer over the Antarctic region. This is largely caused by the release of chlorofluorocarbons (CFCs) in the stratosphere. Ozone (O3) is constantly produced and depleted in the stratosphere from molecular oxygen (O2) and atomic oxygen (O).
$$\mathrm{O+O_2\rightarrow O_3}$$
$$\mathrm{O_3\rightarrow O+O_2}$$
However, chlorine atom (Cl) from CFCs reacts with the ozone in the following equation:
$$\mathrm{Cl+O_3\rightarrow ClO+O_2}$$
$$\mathrm{ClO+O\rightarrow Cl+O_2}$$
(i) Explain the importance of ozone layer to humans. [1 mark]
(ii) CFCs are harmful because they introduce chlorine atoms that reacts with ozone. Even though ozone is constantly produced and depleted, Describe and explain how a single chlorine atom can accelerate the depletion of the ozone layer? [2 marks]
(iii) Suggest two ways to prevent the further depletion of the ozone layer. [2 marks]
$$\mathrm{O+O_2\rightarrow O_3}$$
$$\mathrm{O_3\rightarrow O+O_2}$$
However, chlorine atom (Cl) from CFCs reacts with the ozone in the following equation:
$$\mathrm{Cl+O_3\rightarrow ClO+O_2}$$
$$\mathrm{ClO+O\rightarrow Cl+O_2}$$
(i) Explain the importance of ozone layer to humans. [1 mark]
(ii) CFCs are harmful because they introduce chlorine atoms that reacts with ozone. Even though ozone is constantly produced and depleted, Describe and explain how a single chlorine atom can accelerate the depletion of the ozone layer? [2 marks]
(iii) Suggest two ways to prevent the further depletion of the ozone layer. [2 marks]