C23 conservation of materials in the environment

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C23 conservation of materials in the environment

  1. 1. <ul><li>Explain the importance of metals and their compounds to living systems and environment </li></ul><ul><li>Describe the carbon cycle </li></ul><ul><li>State the importance of the carbon cycle to living systems </li></ul><ul><li>Describe the nitrogen cycle </li></ul><ul><li>State the importance of the nitrogen cycle to living systems </li></ul>Chapter 23 Conservation of Materials in the Environment Learning Outcomes
  2. 2. Chapter 23 Importance of Metals in Living Systems Conservation of Materials in the Environment <ul><li>Metal ions regulate metabolic mechanisms </li></ul><ul><li>Macronutrients are required in larger amounts </li></ul><ul><li>e.g. Na, K, Ca, Mg </li></ul><ul><li>Micronutrients or trace elements </li></ul><ul><li>e.g. Fe, Zn, Cr, Co, Ni, Cu, Mn, Mo, Se </li></ul><ul><li>Plants get their supply of trace metals from soil </li></ul><ul><li>Animals get their supply of trace metals from consuming plants or other sources such as supplements </li></ul><ul><li>Deficiencies and overdoses of nutrients lead to several health problems </li></ul>
  3. 3. Chapter 23 Importance of Metals in Living Systems Conservation of Materials in the Environment Element Function in human body Function in plants Ca <ul><li>Constituent of bones and teeth </li></ul><ul><li>Essential for muscle contractions </li></ul><ul><li>Essential part of cell wall structure </li></ul>K <ul><li>Essential for the nervous system </li></ul><ul><li>Building of protein </li></ul><ul><li>Essential for photosynthesis, fruit quality and reduction of diseases </li></ul>Mg -Essential for the bones and teeth, transmission of nerve impulses and contraction of muscles -Component of chlorophyll in all green plants -Essential for photosynthesis -Activates many plant enzymes needed for growth Fe -Constituent of blood (haemoglobin), bone marrow and liver -Component of the catalyst for chlorophyll production Zn -Essential for growth and cell division, fertility, immune system, growth of skin, hair and nails <ul><li>-Essential for the transformation of carbohydrates </li></ul><ul><li>-Regulates consumption of sugars </li></ul><ul><li>Part of the enzyme systems which regulate plant growth </li></ul>
  4. 4. <ul><li>Trace metals are metals in extremely small quantities, almost at the molecular level, that reside in or are present in animal and plant cells and tissue. </li></ul><ul><li>They are a necessary part of good nutrition, although they can be toxic if ingested in excessive amount. </li></ul><ul><li>Trace metals are depleted through the expenditure of energy by a living organism. </li></ul><ul><li>They are replenished in animals when they eat plants or other animals, and replenished in plants through the uptake of nutrients from the soil. </li></ul><ul><li>Important trace metals include calcium, potassium, magnesium, iron and zinc. </li></ul>Chapter 23 Importance of Trace Metals Conservation of Materials in the Environment
  5. 5. <ul><li>The Earth’s mineral ores are limited and non-renewable. </li></ul><ul><li>If we do not start to conserve and recycle metals, we will ultimately run out of them in the next century. </li></ul>Chapter 23 Conservation of Materials in the Environment Recycling Metals Composition of the Earth’s crust
  6. 6. Chapter 23 Conservation of Materials in the Environment Recycling Metals Advantages Disadvantages <ul><li>Helps to make metals on Earth last longer </li></ul><ul><li>May cause pollution if not carried out properly (e.g. hot toxic metal vapours produced during smelting process of lead-acid batteries) </li></ul><ul><li>Saves the cost of extracting new metals from their ores </li></ul><ul><li>May be more costly than extracting the metal directly from the ground </li></ul><ul><li>Prevents environmental damage and wastage caused by metals being dumped on land </li></ul><ul><li>Current recycling methods for used batteries require lots of energy </li></ul><ul><li>Avoids pollution caused by toxic waste streams when minerals are mined and extracted </li></ul>
  7. 7. <ul><li>The carbon cycle is the circulation of the element carbon in the Earth’s ecosystem. </li></ul>Chapter 23 Carbon Cycle Conservation of Materials in the Environment
  8. 8. <ul><li>Processes which release CO 2 into the atmosphere </li></ul><ul><li>Respiration </li></ul><ul><li>C 6 H 12 O 6 (glucose) + 6O 2  6CO 2 + 6H 2 O + energy </li></ul><ul><li>Combustion </li></ul><ul><li>e.g. burning of fossil fuels such as coal and petroleum </li></ul><ul><li>C + O 2  CO 2 </li></ul><ul><li>Decay and decomposition </li></ul><ul><li>e.g. When plants and animals die, their bodies are broken down by bacteria into CO 2 and other simpler compounds. </li></ul><ul><li>Processes which remove CO 2 from the atmosphere </li></ul><ul><li>Photosynthesis </li></ul><ul><li>e.g. 6CO 2 + 6H 2 O  C 6 H 12 O 6 (glucose) + 6O 2 </li></ul><ul><li>Ocean uptake </li></ul><ul><li>e.g. Oceans are large ‘sinks’ for CO 2 – dissolved atmospheric CO 2 and calcium carbonate shells in marine organisms </li></ul>Chapter 23 Carbon Cycle Conservation of Materials in the Environment
  9. 9. <ul><li>Returning carbon to the soil </li></ul><ul><li>When plants and animals die, decomposers break down their remains into simpler carbon compounds. </li></ul><ul><li>Human activities and the CO 2 level </li></ul><ul><li>CO 2 levels have been steadily rising since the late 19 th century </li></ul><ul><li>The burning of fossil fuels and forests have led to the drastic increase in CO 2 </li></ul><ul><li>Excessive CO 2 in the atmosphere will lead to global warming </li></ul>Chapter 23 Carbon Cycle Conservation of Materials in the Environment
  10. 10. <ul><li>Nitrogen cycle is the circulation of nitrogen and its compounds in the environment. </li></ul>Chapter 23 Nitrogen cycle Conservation of Materials in the Environment
  11. 11. <ul><li>Fixation by lightning </li></ul><ul><li>Formation of nitrogen monoxide: </li></ul><ul><li>N 2 (g) + O 2 (g)  2NO(g) </li></ul><ul><li>Oxidation of nitrogen monoxide: </li></ul><ul><li>2NO(g) + O 2 (g)  2NO 2 (g) </li></ul><ul><li>Formation of nitric acid: </li></ul><ul><li>2NO 2 (g) + H 2 O(l)  HNO 2 (aq) + HNO 3 (aq) </li></ul><ul><li>Formation of nitrates (e.g. reaction with calcium carbonate in soil): </li></ul><ul><li>CaCO 3 (s) + 2HNO 3 (aq)  Ca(NO 3 ) 2 (aq) + CO 2 (g) + H 2 O(l) </li></ul>Chapter 23 Nitrogen cycle Conservation of Materials in the Environment
  12. 12. <ul><li>Fixation by Haber Process </li></ul><ul><li>Nitrogen and hydrogen are chemically combined to form ammonia. </li></ul>Chapter 23 Nitrogen cycle Conservation of Materials in the Environment
  13. 13. <ul><li>Fixation by nitrogen-fixing bacteria </li></ul><ul><li>Nitrogen-fixing bacteria present in soil ‘fix’ or chemically combine N 2 in the atmosphere or soil with hydrogen, oxygen and other elements to produce ammonium salts or nitrates. </li></ul><ul><li>When dead plants and animals decompose, decomposers break down the proteins into simpler substances like nitrates. </li></ul><ul><li>Certain bacteria convert nitrates in the soil into N 2 , which is released into the atmosphere </li></ul>Chapter 23 Nitrogen cycle Conservation of Materials in the Environment
  14. 14. <ul><li>The continuous movement of water between the Earth’s surface and the atmosphere is known as the water cycle or hydrologic cycle. </li></ul><ul><li>Solar and gravitational energies enable the cycle to continue. </li></ul>Chapter 23 Water cycle Conservation of Materials in the Environment
  15. 15. Chapter 23 Conservation of Materials in the Environment
  16. 16. <ul><li>Evaporation </li></ul><ul><li>- The transformation of liquid water into water vapour from water bodies into the </li></ul><ul><li>atmosphere </li></ul><ul><li>Condensation and precipitation </li></ul><ul><li>- Condensation of water vapour into tiny droplets of water </li></ul><ul><li>- When water droplets become too heavy, they fall back to the Earth as rain, snow, </li></ul><ul><li>sleet or hailstones </li></ul><ul><li>Run-off </li></ul><ul><li>- Water runs off the surface to form streams, rivers and lakes </li></ul><ul><li>Infiltration </li></ul><ul><li>- Flow of water from the surface into the ground </li></ul><ul><li>- Infiltrated water becomes soil moisture or groundwater </li></ul>Chapter 23 Water cycle Conservation of Materials in the Environment

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