Chemistry

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Across
  1. 1. when do respiration we produce ?
  2. 7. salt
  3. 9. name of element Hg?
  4. 11. gold
  5. 12. 78% composition in air
  6. 13. the sum of proton number and neutron number
  7. 14. fertilizer
Down
  1. 2. plant need to do photosynthesis
  2. 3. proton number is 6, nucleon number is 12
  3. 4. C8H10
  4. 5. mostly used in balloon
  5. 6. name of element Pb?
  6. 8. important for FEMALE
  7. 10. tin