DGS Yr7 Chemical Reactions

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Across
  1. 2. (3 words) the principle that in any chemical reaction the total mass of the reactants is equal to the total mass of the products
  2. 4. (2 words) a change in which the form of substances change but the composition remains the same - generally reversible
  3. 5. a chemcial reaction in which energy is transferred from the thermal store of the surroundings to the chemical store of the reactants and products
  4. 7. (2 words) a reaction in which atoms are rearranged to form new substances - generally irreversible
  5. 8. (2 words) variables that may assume any value in a range e.g. mass of students in a class
  6. 10. a chemcial reaction in which energy is transferred from the chemical store of the reactants and products to the thermal store of the surroundings
  7. 12. the substances that are formed in a chemical reaction
  8. 13. a chemical reaction in which compound breaks down into simpler compounds or elements
  9. 15. (2 words) fuels derived from the breakdown of living things over millions of years to form oil and natural gas
Down
  1. 1. (2 words) variables that occupy entirely separate categories e.g. types of fruit
  2. 3. (2 words) cannot be replaced once they have been used
  3. 6. the process whereby a substance burns
  4. 9. the starting substances in a chemical reaction
  5. 11. a chemical reaction in which a substance combine with oxygen
  6. 14. a substance that speeds up a chemical reaction but is not used up in the reaction
  7. 16. a substance that burns to transfer energy by heating in a useful way