Lab-Aids Ch. 4 "Physical and Chemical Changes"

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Across
  1. 1. Describes a chemical change that rearranges atoms into different substances.
  2. 4. The initial energy required to get a reaction started.
  3. 5. The tendency of elements to form chemical bonds.
  4. 6. A fundamental property of matter that comes in positive and negative.
  5. 9. A reaction where less energy is absorbed into the reactants from the surroundings and more energy is given off by the products; the enthalpy change is -.
  6. 10. A reaction where more energy is absorbed into the reactants from the surroundings and less energy is given off by the products; the enthalpy change is +.
  7. 16. A measurement or scale of the H+ concentration that tells whether a solution is an acid or a base. Pure water has a = 7.0, < 7 are acidic, > 7 are basic.
  8. 17. A relatively strong connection between 2 atoms.
  9. 19. A chemical that dissolves in water to create less H+ ions than there are in pure water (or equivalently, more OH- ions.
  10. 20. A change in physical properties, such as phase, shape, or temperature; for example, grinding, melting, boiling, dissolving, heating or cooling.
  11. 21. A chemical that dissolves in water to create more H+ than there are in neutral water.
  12. 23. A tiny, positively charged particle in the nucleus of an atom.
  13. 27. Substances that are used and changed in a chemical reaction- the starting materials in a chemical reaction.
  14. 28. An insoluble compound (often a solid), that forms from a chemical reaction in aqueous solution.
  15. 29. The change in energy when 1 mole of a compound is assembled from pure elements.
  16. 32. A tiny, negatively charged particle that fills the outer volume of an atom and is responsible for the formation of chemical bonds.
  17. 33. The exothermic reactions that most living things use to release energy (A.T.P.) for a cell's use.
Down
  1. 2. A chemical reaction that decreases the charge of an atom or ion by accepting electrons- gain of electrons. Element charge decreases.
  2. 3. A neutral group of atoms that are covalently bonded together into a single unit.
  3. 7. Relatively weak forces between molecules.
  4. 8. A change that affects the structure or composition of the molecules that make up a substance, typically turning 1 substance into another substance with different physical properties, a result of a chemical reaction.
  5. 11. A chemical reaction that increases the charge of an atom or ion by giving up electrons- loss of electrons- element charge increases.
  6. 12. An attraction between oppositely charged metals and nonmetals that occurs due to the transfer of electrons from a metal to a nonmetal.
  7. 13. The tiny core of an atom that contains all of the protons and neutrons. This area is extraordinarily small- about 1/10,000 the diameter of the atom.
  8. 14. The endothermic reactions used by autotrophs to convert SOLAR ENERGY into chemical energy.
  9. 15. Strong forces that bond atoms together into molecules or ions.
  10. 18. Describes a chemical equation which satisfies the law of conservation of mass (matter) because the total # of atoms of each type of element are the same on the reactants and products side of the equation.
  11. 22. A chemical bond that consists of 1, 2, or three pairs of shared electrons between nonmetallic elements.
  12. 24. The number out in front of an element or compound which tells you how many moles of each substance participate and are formed in a chemical reaction.
  13. 25. Describes reactants and/or products in chemical reactions that are dissolved in water and therefore more likely to react to form new substances. However, water is not affected by the reaction.
  14. 26. Describes an atom or molecule that has zero electric charge due to it having equal numbers of protons and neutrons.
  15. 30. A substance that is created or released in a chemical reaction.
  16. 31. An ionic compound in which the + ion comes from a base and the negative ion comes from an acid or an ionic compound that dissolves in water to produce ions.