reactions year 8

1234567891011121314151617181920
Across
  1. 3. the total mass of reactants and products are always the same. what is this called
  2. 4. these fuels are non renewable
  3. 6. the minimum energy needed for a reaction to occur
  4. 7. the element with the symbol 'Na'
  5. 9. dioxide a gas produced when fossil fuels burn
  6. 13. the element with the symbol 'Pb'
  7. 14. all things are made up of these tiny units
  8. 18. a gas needed for burning
  9. 19. graphs or diagrams that show the energy changes in a recation
Down
  1. 1. the element with the symbol 'K'
  2. 2. reactions that release heat energy to the surroundings
  3. 5. another word for burning
  4. 8. there are 3 fossil fuels coal oil and which other
  5. 10. a sign of a chemical reaction taking place
  6. 11. substances that react together, shown before the arrow in the equation
  7. 12. the element with the symbol 'Fe'
  8. 15. a reaction that is irreversible involves this type of change
  9. 16. the positive subatomic particle
  10. 17. a reaction that is reversible involves this type of change
  11. 20. reactions that take in energy from the surroundings