Finite resources from the Earth, oceans and atmosphere are processed to provide energy and materials. Chemistry plays an important role in improving agricultural and industrial processes to provide new products. It’s also important in sustainable development, which is development that meets the needs of current generations without compromising the ability of future generations to meet their own needs. resources given appropriate information. Extract and interpret information about resources from charts, graphs and tables. Use orders of magnitude to evaluate the significance of data. WS 3.2 MS 2c, 2h, 4a 5.10.1.2 Water of appropriate quality is essential for life. For humans, drinking water should have sufficiently low levels of dissolved salts and microbes. Water that is safe to drink is called potable water. Potable water is not pure water in the chemical sense because it contains dissolved substances. Distinguish between potable water and pure water. Describe the differences in treatment of ground water and salty water. Give reasons for the steps used to produce potable water. 2 Define the terms: potable water pure water. Explain the differences between the two terms. Extended writing: describe the process of desalination. Extended writing: describe the process of distillation Required practical 13: Analysis and purification of samples from different sources, including pH, dissolved solids and distillation. AT skills covered by this practical activity: 2, 3 and 4. Video clip YouTube: Resources for schools - clip YouTube:
osmosis. These processes require large amounts of energy. 5.10.1.3 Urban lifestyles and industrial processes produce large amounts of waste water that require treatment before being released into the environment. Sewage and agricultural waste water require removal of organic matter and harmful microbes. Industrial waste water may require removal of organic matter and harmful chemicals. Sewage treatment includes: screening and grit removal sedimentation to produce sewage sludge and effluent anaerobic digestion of sewage sludge aerobic biological treatment of effluent. Comment on the relative ease of obtaining potable water from waste, ground and salt water. 1 Research how water is treated. Extended writing: detail the methods involved. Several water companies provide resources for schools regarding sewage treatment, for example: Video clip YouTube: 5.10.1.4 (HT only) The Earth’s resources of metal ores are limited. Evaluate alternative biological methods of metal extraction, given appropriate information. 1 Extended writing: describe the processes of phytomining Research information for the processes of: phytomining Video clip YouTube:
Copper ores are becoming scarce and new ways of extracting copper from ores include phytomining and bioleaching. These methods avoid traditional mining methods of digging, moving and disposing of large amounts of rock. Phytomining uses plants to absorb metal compounds. The plants are harvested and then burned to produce ash that contains metal compounds. Bioleaching uses bacteria to produce leachate solutions that contain metal compounds. The metal compounds can be processed to obtain the metal. For example, copper can be obtained from solutions of copper compounds by displacement using scrap iron or by electrolysis. bioleaching. Evaluate the impacts and benefits of biological methods of extracting metal. bioleaching. Include percentage of extracted, concentration of global warming gases released, amount of electricity used etc. Use this data in an evaluation. It may be possible to model phytomining in the laboratory by watering geraniums with dilute copper sulphate for a period of time. The leaves can be burnt and copper can be extracted from the ash by rinsing in dilute hydrochloric acid and electrolysing the solution.
Selective or abbreviated LCAs can be devised to evaluate a product but these can be misused to reach conclusions, eg in support of claims for advertising purposes. 5.10.2.2 The reduction in use, reuse and recycling of materials by end users reduces the use of limited resources, energy consumption, waste and environmental impacts. Metals, glass, building materials, clay ceramics and most plastics are produced from limited raw materials. Much of the energy used in the processes comes from limited resources. Obtaining raw materials from the Earth by quarrying and mining causes environmental impacts. Some products, such as glass bottles, can be reused. Glass bottles can be crushed and melted to make different glass products. Other Evaluate ways of reducing the use of limited resources, given appropriate information. 1 Discuss the issues relating to using limited resources to generate energy. Extended writing: describe the environmental impacts of obtaining raw materials from the Earth. Research methods of producing/obtaining metal/glass/building materials/clay ceramics/plastics. Identify in these methods the limited resources that are used to generate the energy. Research how glass is recycled. Research how metal is recycled and alternatives for use of scrap metals ie in obtaining iron in a blast furnace. Video clip YouTube: