chemistry crossword

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Across
  1. 2. compound that dissolves in water to form a solution with a pH lower than 7
  2. 4. principle that matter is not created or destroyed in a chemical reaction; the mass of the products always equals the mass of the reactants
  3. 5. group 2 elements in the periodic table; their reactivity is not as strong as that of the alkali metals
  4. 10. measure of atomic mass; 1 amu is equal to 1/12 the mass of a carbon 12 atom
  5. 12. chemical combination of two or more elements in a specific ratio
  6. 14. catalyst involved in chemical reactions in living things
  7. 16. chemical reaction that releases energy
  8. 17. an experiment in which all reactants and all products of a chemical reaction are accounted for
  9. 19. slow chemical change that occurs when oxygen in the air reacts with a metal
  10. 21. number of protons in the nucleus of one atom of an element
Down
  1. 1. group 1 elements in the periodic table, not including hydrogen; the most reactive of the metals
  2. 3. description of how a substance interacts with other substances, such as acids;chemical properties are observable only when a chemical change occurs
  3. 4. colourless, odourless gas;produced by incomplete combustion of chemicals containing carbon (e.g. hydrocarbons); major source: motor vehicles
  4. 6. the smallest part of an element that is representative of that element; a neutral particle made up of a nucleus containing protons and neutrons, and in which the number of electrons equals the number of protons
  5. 7. mass mass of one atom of an element calculated from the total number of protons,neutrons, and electrons of that atom; measured in atomic mass units (amu)
  6. 8. change of state from a gas to a liquid
  7. 9. ability of a substance to conduct electricity or heat
  8. 11. a reaction that takes place when two or more substances react to form new substances
  9. 13. change that results when two or more substances react to create a different substance or substances; the new substances have completely different properties from the original ones
  10. 15. combination of symbols that represent a compound; the formula identifies the elements in the compound and the amount of each element
  11. 17. chemical reaction that occurs when oxygen reacts with a substance to form a new substance and give off energy
  12. 18. cloudy mixture in which tiny particles of one substance are held within another and particles cannot be separated out from the other substance
  13. 20. change of state from a gas to a solid