8 Ch2 Science Drennan

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Across
  1. 2. Reaction is a chemical reaction that releases thermal energy.
  2. 6. A reaction, the negative ions in two compounds switch places, forming two new compounds.
  3. 10. A description of a reaction using element symbols and chemical formulas.
  4. 13. The starting substances in a chemical reaction.
  5. 15. The minimum amount of energy needed to start a chemical reaction.
  6. 17. A reaction, one compound breaks down and forms two or more substances.
Down
  1. 1. A process in which atoms of one or more substances rearrange to form one or more new substnces.
  2. 3. A number placed in front of an element symbol or chemical formula in an equation.
  3. 4. A reaction, one element replaces another element in a compound.
  4. 5. A chemical reaction in which a substance combines with oxygen and releases energy.
  5. 7. The substances produced by the chemical reaction.
  6. 8. A type of chemical reaction in which two or more substances combine and form one compound
  7. 9. States that the total mass of the reactants before a chemical reaction is the same as the total mass of the products after the chemical reaction.
  8. 11. A catalyst that speeds up chemical reactions in living cells.
  9. 12. A substance that increases reaction rate by lowering the activation energy of a reaction.
  10. 14. Chemical reactions that absorb thermal energy.
  11. 16. A substance that slows, or even stops, a chemical reaction.