chemistry

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Across
  1. 2. a gas lighter than air
  2. 4. C
  3. 7. mass divided by volume
  4. 8. an air like substance
  5. 9. mass divided by density
Down
  1. 1. firm shape
  2. 2. H
  3. 3. volume divided by density
  4. 5. O
  5. 6. a substance that fills a shape of a container