chemicals and chemical change n.
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  1. CHEMICALS AND CHEMICAL CHANGE Chapter 5.1 BLM 5.1a, 5.1b

  2. Chemicals and chemical Change CHEMISTRY – is the study of matter, its changes and its properties MATTER – is anything that has mass and takes up space ATOM – the smallest particle of matter

  3. HANDOUT 5.1a Use the following labels and pages 172 – 173 to complete the handout Chemical changes, C , heterogeneous mixtures, elements, pure substances (x2), atoms (x2), NaCl, chemical formulas, chemical symbols, physical changes, O, solutions, H2O, molecules, O2 , compounds

  4. Pure Substance Heterogeneous Mixture Elements Compounds Pure Substance Chemical Symbols Chemical Formulas Solutions Molecules Atoms O C NaCl H2O Atoms Physical Changes O2 Chemical Changes

  5. PHYSICAL CHANGE – a change in a substance which does not produce a new substance. EXAMPLE: melting ice CHEMICAL CHANGE – a change in a substance which does produce a new substance. EXAMPLE: match burning

  6. Signs of a Chemical Change • Colour change • Energy given off (heat or light) • Gas formed • Precipitate formed • Tough to reverse

  7. HANDOUT 5.1b Use the following labels and pages 173 – 174 to complete the handout Rusting/corrosion, difficult to reverse, water vapour, turns cloudy, new colour, reactants, pops, oxygen (x2), turns pink, products, precipitate, carbon dioxide, bursts into flames, heat or light, hydrogen

  8. Corrosion or Rusting Reactants Products Oxygen Colour Change Tough toreverse Energy Given off Precipitate forms O2 CO2 H2O H2 Turns Cloudy Turns Pink Bursts into Flames Pops

  9. HOMEWORK QUESTIONS • Page 175 • QUESTIONS: #1,2,4,5,6,7

  10. SOLUTIONS TO HOMEWORK QUESTIONS Q1 – classify each of the following as a pure substance or a mixture A) soapy water MIXTURE B) hydrogen gas PURE SUBSTANCE C) sodium chloride PURE SUBSTANCE

  11. QUESTION2 Classify each of the following as an element or a compound. A) hydrogen ELEMENT B) potassium carbonate COMPOUND C) water COMPOUND D) Mg ELEMENT

  12. QUESTION 4 Classify each of the following as a physical property or a chemical property. A) Gasoline is a clear pink solution PHYSICAL PROPERTY B) Gasoline burns in air CHEMICAL PROPERTY C) Water boils at 1100C. PHYSICAL PROPERTY D) electric current can split water into hydrogen and oxygen gases CHEMICAL PROPERTY

  13. QUESTION 5 When aluminum metal is added to hydrobromic acid, hydrogen gas and an aluminum bromide solution are formed. A) What kind of change has occurred? Chemical, bubbles formed, new substance made

  14. QUESTION 5 When aluminum metal is added to hydrobromic acid, hydrogen gas and an aluminum bromide solution are formed B) Which substances are the reactants and which are the products? Reactants – Aluminum and Acid Products – Hydrogen + Aluminum Bromide

  15. QUESTION 6 Describe the chemical tests that can be used to identify the following gases. A) hydrogen a flaming wooden splint causes a “pop” B) Oxygen a glowing wooden splint relights (bursts into flame)

  16. QUESTION 6 C) Carbon Dioxide A burning wooden splint extinguishes, OR when the gas is bubbled through limewater, the limewater changes from a clear, colourless solution to a cloudy white liquid (a precipitate is formed)

  17. QUESTION 6 Water Vapour Changes the colour of cobalt chloride test paper from blue to pink

  18. QUESTION 7 When sodium carbonate is added to water, the sodium carbonate dissolves. When hydrochloric acid is added to the solution, the solution fizzes. What kinds of changes have occurred?

  19. QUESTION 7 - ANSWER When sodium carbonate dissolves in water it is a physical change A chemical change happens when gas is formed after hydrochloric acid is added ( fizz / Bubbles )