Changing Matter Page 144
Objectives <ul><li>To state the 2 different types of changes </li></ul><ul><li>To compare between physical and chemical ch...
Animation Changes
Types of Changes <ul><li>Physical change </li></ul><ul><li>Chemical change </li></ul>
Physical change <ul><li>Change in which no new substance is formed </li></ul><ul><li>Can be reversed </li></ul><ul><li>Exa...
Chemical change <ul><li>Change in which new substance is formed </li></ul><ul><li>Difficult to reverse, permanent change <...
Chemical change <ul><li>Change in which new substance is formed </li></ul><ul><li>Difficult to reverse, permanent change <...
Differences between physical and chemical change Permanent Temporary  Hard to reverse Can be reversed New substance formed...
Do checkpoint & Inquiry Time Page 145
What happens when matter changes? <ul><li>Sometimes heat energy is given out to bring about change </li></ul><ul><ul><li>B...
Changes involving… <ul><li>Heat </li></ul><ul><li>Light </li></ul><ul><li>Electricity </li></ul><ul><li>Mixing </li></ul>
Chemical reaction <ul><li>At least  two reactants </li></ul><ul><li>Chemical changes occur at a molecular level where bond...
Changes involving heat <ul><li>Heat causes </li></ul><ul><ul><li>Expansion and contraction </li></ul></ul><ul><ul><li>Chan...
Changes involving heat <ul><li>Exothermic </li></ul><ul><ul><li>Reactions occur spontaneously and energy can be released i...
Changes involving heat <ul><li>Endothermic </li></ul><ul><ul><li>Cannot occur spontaneously </li></ul></ul><ul><ul><li>Req...
Changes involving heat <ul><li>Different types of chemical reactions </li></ul><ul><ul><li>Combination </li></ul></ul><ul>...
Combination <ul><li>Heat causes 2 substances to combine to form new substances </li></ul><ul><li>Example: combination of i...
Thermal decomposition <ul><li>Breaking down of substances into 2 or more simpler substances </li></ul><ul><li>Example: dec...
Combustion or burning <ul><li>Substances that combine with oxygen when heated to form new substances </li></ul><ul><li>Exa...
Changes involving light Photosynthesis <ul><li>Light energy is absorbed by green plants to make food (glucose) </li></ul><...
Changes involving light Photography <ul><li>Black and white photographic film contains silver bromide </li></ul><ul><li>Ex...
Changes involving electricity <ul><li>Electricity involved in many physical and chemical changes </li></ul><ul><li>Electri...
Changes involving Electricity Electrolysis <ul><li>It is the chemical decomposition of an electrolyte by an electric curre...
Changes involving mixing <ul><li>Two or more substances are mixed together, they may react chemically </li></ul><ul><li>Ex...
Do checkpoint pg 150 <ul><li>Exothermic: reaction in which heat energy is given out </li></ul><ul><li>Endothermic: reactio...
Short animation Air pollution
Effects of Burning Fuels <ul><li>Causes air pollution, acid rain and leads to global warming </li></ul><ul><li>Air polluti...
Common air pollutants <ul><li>Gases </li></ul><ul><ul><li>Carbon monoxide </li></ul></ul><ul><ul><li>Sulphur dioxide </li>...
What are the effects of air pollution? <ul><li>Breathe smoke, the smoke stick onto our lungs. Cause cough and lung cancer ...
What are the effects of air pollution? <ul><li>Sulphur dioxide and nitrogen dioxide dissolved in rain to become acid rain ...
What are the effects of air pollution? <ul><li>Incomplete combustion due to insufficient supply of oxygen produce carbon m...
Do checkpoint pg 152 <ul><li>Sulphur dioxide, nitrogen dioxide, carbon dioxide and solid (soot) particles </li></ul><ul><l...
Short animation Global warming
Global warming <ul><li>Burning fuels also produce carbon dioxide </li></ul><ul><li>Carbon dioxide trap heat from the sun <...
Global warming <ul><li>Melting ice raises the sea level and some coastal areas will become flooded </li></ul>
Short animation Greenhouse effects
Short animation Human and the environment
Saving the environment <ul><li>Use public transport instead of cars </li></ul><ul><li>Use solar powered devices </li></ul>...
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Changing Matter

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Changing Matter

  1. 1. Changing Matter Page 144
  2. 2. Objectives <ul><li>To state the 2 different types of changes </li></ul><ul><li>To compare between physical and chemical change </li></ul>
  3. 3. Animation Changes
  4. 4. Types of Changes <ul><li>Physical change </li></ul><ul><li>Chemical change </li></ul>
  5. 5. Physical change <ul><li>Change in which no new substance is formed </li></ul><ul><li>Can be reversed </li></ul><ul><li>Examples: </li></ul><ul><ul><li>Salt dissolves in water to form salt solution </li></ul></ul><ul><ul><li>Evaporation of sweat in the skin </li></ul></ul><ul><ul><li>Evaporation of water from the roads </li></ul></ul><ul><ul><li>Melting ice cream or chocolate </li></ul></ul><ul><ul><li>Boiling water </li></ul></ul><ul><ul><li>Expansion and contraction of metal </li></ul></ul>
  6. 6. Chemical change <ul><li>Change in which new substance is formed </li></ul><ul><li>Difficult to reverse, permanent change </li></ul><ul><li>Examples: </li></ul><ul><ul><li>Iron rust </li></ul></ul><ul><ul><li>Apple turning brown </li></ul></ul><ul><ul><li>Cooking food </li></ul></ul><ul><ul><li>Respiration </li></ul></ul><ul><ul><li>Photosynthesis </li></ul></ul><ul><ul><li>Baking bread/cake </li></ul></ul><ul><ul><li>Rotting of food </li></ul></ul>
  7. 7. Chemical change <ul><li>Change in which new substance is formed </li></ul><ul><li>Difficult to reverse, permanent change </li></ul><ul><li>Examples: </li></ul><ul><ul><li>Iron rust </li></ul></ul><ul><ul><li>Apple turning brown </li></ul></ul><ul><ul><li>Cooking food </li></ul></ul><ul><ul><li>Respiration </li></ul></ul><ul><ul><li>Photosynthesis </li></ul></ul><ul><ul><li>Baking bread/cake </li></ul></ul><ul><ul><li>Rotting of food </li></ul></ul>
  8. 8. Differences between physical and chemical change Permanent Temporary Hard to reverse Can be reversed New substance formed No new substance formed Chemical change Physical change
  9. 9. Do checkpoint & Inquiry Time Page 145
  10. 10. What happens when matter changes? <ul><li>Sometimes heat energy is given out to bring about change </li></ul><ul><ul><li>Burning of charcoal </li></ul></ul><ul><li>Sometimes heat energy is needed to bring about change </li></ul><ul><ul><li>Toasting bread </li></ul></ul>
  11. 11. Changes involving… <ul><li>Heat </li></ul><ul><li>Light </li></ul><ul><li>Electricity </li></ul><ul><li>Mixing </li></ul>
  12. 12. Chemical reaction <ul><li>At least two reactants </li></ul><ul><li>Chemical changes occur at a molecular level where bonds are broken and formed again </li></ul><ul><li>Molecular structure is changed </li></ul><ul><li>Two or more reactants combine to form one or more products </li></ul><ul><li>Left hand side shows the reactants and the right hand side shows the products </li></ul><ul><li>Reactant A + Reactant B -> Product C + Product D </li></ul>
  13. 13. Changes involving heat <ul><li>Heat causes </li></ul><ul><ul><li>Expansion and contraction </li></ul></ul><ul><ul><li>Changes of state such as melting and boiling </li></ul></ul><ul><li>Heat involved in chemical reaction </li></ul><ul><li>Chemical reaction that gives out heat energy – EXOTHERMIC </li></ul><ul><li>Chemical reaction that takes in heat energy - ENDOTHERMIC </li></ul>
  14. 14. Changes involving heat <ul><li>Exothermic </li></ul><ul><ul><li>Reactions occur spontaneously and energy can be released in the form of heat, light or sound </li></ul></ul><ul><ul><li>Examples, sodium reacts with chlorine to form common salt </li></ul></ul><ul><ul><ul><li>Heat and light are given out </li></ul></ul></ul>
  15. 15. Changes involving heat <ul><li>Endothermic </li></ul><ul><ul><li>Cannot occur spontaneously </li></ul></ul><ul><ul><li>Require energy in order to get these reactions to occur </li></ul></ul><ul><ul><li>Example: Photosynthesis: require light energy to break the bonds of carbon dioxide and water </li></ul></ul>
  16. 16. Changes involving heat <ul><li>Different types of chemical reactions </li></ul><ul><ul><li>Combination </li></ul></ul><ul><ul><li>Thermal decomposition </li></ul></ul><ul><ul><li>Combustion or burning </li></ul></ul>
  17. 17. Combination <ul><li>Heat causes 2 substances to combine to form new substances </li></ul><ul><li>Example: combination of iron and sulphur to form iron sulphide </li></ul><ul><li>Iron + sulphur  iron sulphide </li></ul>heat
  18. 18. Thermal decomposition <ul><li>Breaking down of substances into 2 or more simpler substances </li></ul><ul><li>Example: decomposition of sugar </li></ul><ul><li>Sugar  carbon + water vapour </li></ul>heat
  19. 19. Combustion or burning <ul><li>Substances that combine with oxygen when heated to form new substances </li></ul><ul><li>Example: charcoal burning </li></ul><ul><li>When charcoal is burnt oxygen is needed, the addition of oxygen to a substance is called OXIDATION </li></ul><ul><li>Carbon + oxygen  carbon dioxide </li></ul>heat
  20. 20. Changes involving light Photosynthesis <ul><li>Light energy is absorbed by green plants to make food (glucose) </li></ul><ul><li>Carbon dioxide + water  glucose + oxygen </li></ul>light
  21. 21. Changes involving light Photography <ul><li>Black and white photographic film contains silver bromide </li></ul><ul><li>Exposure to light decomposes the silver bromide into silver </li></ul><ul><li>Produces dark areas on the film </li></ul><ul><li>Greater the exposure to light, the darker the area on the film </li></ul>
  22. 22. Changes involving electricity <ul><li>Electricity involved in many physical and chemical changes </li></ul><ul><li>Electric current passes through the filament of an electric light bulb, the filament heats up and glows. </li></ul><ul><li>When current is passed through a liquid that conduct electricity, chemical reaction called ELECTROLYSIS </li></ul>
  23. 23. Changes involving Electricity Electrolysis <ul><li>It is the chemical decomposition of an electrolyte by an electric current </li></ul><ul><li>Application of electrolysis: </li></ul><ul><ul><li>Extract metals such as sodium, magnesium and aluminium from their molten compounds </li></ul></ul><ul><ul><li>Prepare gases such as chlorine </li></ul></ul><ul><ul><li>Refine metals such as copper and zinc </li></ul></ul>
  24. 24. Changes involving mixing <ul><li>Two or more substances are mixed together, they may react chemically </li></ul><ul><li>Example of physical change: sugar mix with water </li></ul><ul><li>Examples of chemical changes: </li></ul><ul><ul><li>Magnesium added to hydrochloric acid </li></ul></ul><ul><ul><li>Acids and carbonates </li></ul></ul><ul><ul><li>Acid and alkali </li></ul></ul>
  25. 25. Do checkpoint pg 150 <ul><li>Exothermic: reaction in which heat energy is given out </li></ul><ul><li>Endothermic: reaction in which heat energy is take in/absorbed </li></ul><ul><li>Combination, thermal decomposition and combustion </li></ul>
  26. 26. Short animation Air pollution
  27. 27. Effects of Burning Fuels <ul><li>Causes air pollution, acid rain and leads to global warming </li></ul><ul><li>Air pollution can cause respiratory diseases, skin and eye irritations </li></ul><ul><li>Main source of air pollutants is burning of fuels in power stations and vehicle engines </li></ul>
  28. 28. Common air pollutants <ul><li>Gases </li></ul><ul><ul><li>Carbon monoxide </li></ul></ul><ul><ul><li>Sulphur dioxide </li></ul></ul><ul><ul><li>Nitrogen dioxide </li></ul></ul><ul><li>Solid </li></ul><ul><ul><li>Ash </li></ul></ul><ul><ul><li>Dust </li></ul></ul><ul><ul><li>Soot </li></ul></ul>
  29. 29. What are the effects of air pollution? <ul><li>Breathe smoke, the smoke stick onto our lungs. Cause cough and lung cancer </li></ul><ul><li>Sulphur dioxide and nitrogen dioxide hurt the eyes, make breathing difficult and can cause lung diseases. Plants cannot grow well too </li></ul>
  30. 30. What are the effects of air pollution? <ul><li>Sulphur dioxide and nitrogen dioxide dissolved in rain to become acid rain </li></ul><ul><li>Corrodes metal and concrete building </li></ul><ul><li>Harms plant life and affects aquatic organisms </li></ul>
  31. 31. What are the effects of air pollution? <ul><li>Incomplete combustion due to insufficient supply of oxygen produce carbon monoxide </li></ul><ul><li>Brain damage and death </li></ul><ul><li>Prevents red blood cells from combining with oxygen </li></ul><ul><li>Can pass on to an unborn child in a pregnant woman. Born prematurely, underweight or dead </li></ul>
  32. 32. Do checkpoint pg 152 <ul><li>Sulphur dioxide, nitrogen dioxide, carbon dioxide and solid (soot) particles </li></ul><ul><li>The burning of fuels in power stations and vehicle engines </li></ul><ul><li>Sulphur dioxide and nitrogen dioxide </li></ul><ul><li>Kill plants, fish and damage buildings and statues </li></ul>
  33. 33. Short animation Global warming
  34. 34. Global warming <ul><li>Burning fuels also produce carbon dioxide </li></ul><ul><li>Carbon dioxide trap heat from the sun </li></ul><ul><li>This is important to keep the Earth warm </li></ul><ul><li>Carbon dioxide and other gases (sulphur dioxide and nitrogen dioxide) that trap heat are called greenhouse gases </li></ul><ul><li>Global warming causes drastic changes in the climate and ice to melt faster in the polar region </li></ul>
  35. 35. Global warming <ul><li>Melting ice raises the sea level and some coastal areas will become flooded </li></ul>
  36. 36. Short animation Greenhouse effects
  37. 37. Short animation Human and the environment
  38. 38. Saving the environment <ul><li>Use public transport instead of cars </li></ul><ul><li>Use solar powered devices </li></ul><ul><li>Conserve energy </li></ul>

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