Chemical Reaction crosssword puzzle

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Across
  1. 2. hard
  2. 4. Iron
  3. 8. (N2+H2)
  4. 9. 2become1
  5. 10. (NH3)
  6. 11. IronRusting
  7. 13. (CH+O2=CO2+H2O)
  8. 16. water
  9. 17. tea
  10. 18. 2atoms
  11. 19. water+CarbonDioxide+Sun+Oxygen
  12. 20. Hydrogen
Down
  1. 1. molecules
  2. 3. (BaCl2+MgSO4=BaSO4+MgCl2)
  3. 5. (N2+H2=NH3)
  4. 6. oxygen
  5. 7. (N2+H2=NH3)
  6. 12. 1atom
  7. 14. ions
  8. 15. decaying