chemical reactions

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Across
  1. 4. all symbol equations must be this
  2. 5. used to test for carbon dioxide
  3. 9. the chemicals made in a reaction
  4. 13. reaction where heat is transferred to the surroundings
  5. 14. the mass of reactants always equals the mass of the products
  6. 17. a fuel made millions of years ago
  7. 19. change where a chemical changes form but is the same substance
Down
  1. 1. when iron is oxidised
  2. 2. speeds up a reaction but is not used up
  3. 3. decomposition using heat
  4. 6. in an equation means react to make
  5. 7. reaction where heat is taken in from the surroundings
  6. 8. burning
  7. 10. reaction when a substance is broken down into simpler substances
  8. 11. will run out one day
  9. 12. the chemicals used to start a reaction
  10. 15. a chemical reaction where oxides are made
  11. 16. change when 2 reactants form a new substance
  12. 18. burns to release energy