Chapter 14

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Chapter 14
2010-03-30 22:25:26

Chemical Reactions
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  1. What is a chemical reaction?
    A chemical reaction is the process by which one or more substances change to produce one or more different substances.
  2. What are four signs that determine that a chemical reaction has taken place?
    Four signs that determine that a chemical reaction has taken place is gas formation, solid formation, energy change, and color change. A gas formation is when gas forms from a reaction of two or more elements. Solid formation is when a solid forms and changes its matter. Energy change is when energy is released. Lastly, color change is when an element or object changes its color.
  3. What is a precipitate?
    A precipitate is a solid that is produced as a result of a chemical reaction in a solution. An example is a cake.
  4. What is a chemical bond?
    A chemical bond is a force that holds two atoms together in a molecule.
  5. A chemical ______ describes a chemical reaction.
  6. The substances formed from a chemical reaction are ______.
  7. How does a balanced chemical equation illustrate that mass is never lost or gained in a chemical reaction?
    A balanced equation illustrates the law of conservation of mass: mass is neither created nor destroyed during ordinary physical and chemical changes.
  8. What is the difference between a subscript and a coefficient?
    The difference between a subscript and a coefficient is that a subscript can only apply to one element while a coefficient can apply to one or more elements. Also, a coefficient is placed in front of a chemical symbol or formula, while a subscript is a number written to the right and below of a chemical symbol.
  9. How can you balance a chemical equation?
    You can balance a chemical equation by adding coefficient.
  10. What do the prefixes mono-, di-, tri-, tetra-, penta-, hexa-, hepta-, octa-, nona-, deca- mean?
    Mono- 1, di- 2, tri- 3, tetra- 4, penta- 5, hexa- 6, hepta- 7, octa- 8, nona- 9, deca- 10.
  11. What are the four chemical reactions? What happens during each?
    The four chemical reactions are synthesis, decomposition, single-displacement, and double-displacement. A synthesis reaction is a reaction when two or more elements combine and form a new compound. Decomposition reaction is when a compound breaks down and forms two or more elements. Single-displacement reaction is when one element takes the place of another element in a compound. A double-displacement reaction is when two reactants exchange ions to form two new compounds .
  12. What causes chemical bonds in molecules to break?
    A lot of energy is what causes chemical bonds in molecules to break. If there is enough energy, when molecules bump into each other, the chemical bonds in the molecules break.
  13. How do substances form a chemical reaction?
    New substances form in a chemical bond by first breaking chemical bonds in the starting substances, which takes energy. The atoms then rearrange and new bonds form to make new substances.
  14. What is an ion?
    An ion is a charged particle that forms when an atom or group of atoms gains or loses one or more electrons.
  15. What is the charge of an ionic compound?
    The charge of an ionic compound is neutral. It is neutral because it is a bond of ions and since ions are both negative and positive charged the charges cancel eachother out to make the compound neutral.
  16. What is an example of chlorophyll?
    An example of chlorophyll is a leaf.