Beatty 18.1_Air_WS1_Answers 1

1 Beatty Secondary School Science Department (Chemistry Unit) Chemistry 6092 Name: ___________________________________ ( ) Date: _______________ Class: 4E1 TOPIC: AIR – ATMOSPHERE & ENVIRONMENT (WORKSHEET 1) Learning Objectives: (a) Describe the volume composition of gases present in dry air as being approximately 78% nitrogen, 21% oxygen and the remainder being noble gases (with argon as the main constituent) and carbon dioxide. (b) Name some common atmospheric pollutants, e.g. ca rbon monoxide; methane; nitrogen oxides (NO and NO2); ozone; sulfur dioxide; unburned hydrocarbons. (c) State the sources of these pollutants as: (i) carbon monoxide from incomplete combustion of carbon-containing substances (ii) nitrogen oxides from lightning activity and internal combustion engines (iii) sulfur dioxide from volcanoes and combustion of fossil fuels (d) Describe the reactions used in possible solutions to the problems arising from som e of the pollutants named (i) the redox reactions in catalytic converters to remove combustion pollutants, (ii) the use of calcium carbonate to reduce the effect of ‘acid rain’ and in flue gas desulfurisation. (e) Discuss some of the effects of these pollutants on health and on the environment: (i) the poisonous nature of carbon monoxide (ii) the role of nitrogen dioxide and sulfur dioxide in the formation of ‘acid rain’ and its effects on respiration and buildings. Multiple-Choice Questions 1 Which of the following noble gases has the highest percentage composition in the air? A argon B helium C neon D xenon ( A ) 2 Which of the following is obtained industrially from the fractional distillation of air? A methane B hydrogen C oxygen D sulfur dioxide ( C ) 3 Which of the following gases is not present in clean air? A oxygen B nitrogen C carbon dioxide D hydrogen ( D ) 4 Which of the following is not a source of sulfur dioxide? A combustion of coal B combustion of crude oil C lightning activity D volcanic eruption ( C )

2 5 Which of the following gases does not affect the pH of water? A carbon dioxide B carbon monoxide C nitrogen dioxide D sulfur dioxide ( B ) 6 Which of these chemicals can be used to test for the presence of sulfur dioxide in polluted air? A aqueous acidified potassium manganate(VII) B anhydrous copper(II) sulfate C aqueous hydrogen peroxide D limewater ( A ) 7 Which of the following about nitrogen dioxide is true? A It is a greenhouse gas. B It is produced when plant and animal matter decay. C It is released during complete combustion of petrol. D It causes acid rain. ( D ) 8 Which of the following is not a harmful effect of carbon monoxide? A It causes headaches. B It causes breathing difficulties. C It causes cancer. D It causes death. (