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Chemical Reaction Notes


Chemical Reaction Notes Chemical Reaction Notes Known amounts of elements, polyatomic ions, and/or compounds can break apart, rearrange, and form ionic or covalent ... – PowerPoint PPT presentation

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Title: Chemical Reaction Notes

Chemical Reaction Notes
Chemical Reaction Notes
  • Known amounts of elements, polyatomic ions,
    and/or compounds can break apart, rearrange, and
    form ionic or covalent bonds in new compounds in
    order to increase stability and decrease the
    total amount of chemical potential energy.

Chemical Reaction Notes
  • These changes are called chemical reactions, and
    are different from the nuclear reactions we
    studied, which are when nuclei come together (or
    split apart) and create new atoms.

Chemical Reaction Notes
  • Chemists represent chemical reactions with
  • There are three types word, skeleton or chemical.

Chemical Reaction Notes
  • Chemical equations consist of a list of formulas
    for all of the reactants (compounds or elements
    added together to begin a chemical reaction) on
    the left side and a list of all of the products
    (compounds or elements which form during a
    chemical reaction) on the right side.

Chemical Reaction Notes
  • Reactants and products are separated by an arrow.
  • Reactants are separated from one another by plus
    signs (as are products).

Chemical Reaction Notes
  • Each formula may be followed by a subscript
    (solid, liquid, gas, aqueous) to show what state
    of matter each compound is in.
  • We may represent energy (heat, light, energy) as
    either a product or a reactant by writing it on
    the appropriate side of the equation.

Chemical Reaction Notes
  • Law of Conservation of Mass In a chemical
    reaction the arrangement of atoms will change,
    but the total number of each type of atom, and
    therefore the total mass, will remain constant.

Chemical Reaction Notes
  • All chemical reactions must obey this law and
    therefore all chemical equations must obey it

Chemical Reaction Notes
  • In order to ensure that our chemical equations
    obey the law of cons. of mass, we balance all of
    our equations.
  • To do this
  • 1. You must make sure that all of the individual
    compounds formulas are correct.
  • (Hydrogen, oxygen, nitrogen, and the halogens are
    all diatomic elements, meaning that whenever they
    are not found in a compound they form a molecule
    with themselves and have a formula with a
    subscript 2). Remember BrINCl HOF!

Chemical Reaction Notes
  • 2. Pick any number and place it as a coefficient
    in front of any compound.
  • 3. You should then balance one element at a time
    from one side of the equation to the other by
    placing coefficients in front of the remaining

Chemical Reaction Notes
  • 4. Multiply coefficients to get rid of fractions
    if necessary.
  • 5. Reduce coefficients if necessary.

Chemical Reaction Notes
  • Special hints
  • 1. Never change your subscripts.
  • 2. Balance elements that only appear in one
    formula on each side first.
  • 3. After your first free choice of a
    coefficient, you must only use coefficients that
    balance the element.
  • Count polyatomic ions as one unit.
  • Balance the element oxygen last.
  • Table Team Practice.

Chemical Reaction Notes
Chemical Reaction Notes
Chemical Reaction Notes
Chemical Reaction Notes
Chemical Reaction Notes
Which of the following is NOT a chemical
reaction? A. a piece of wood burning B. a car
rusting C. an ice cube melting into water D. red
litmus paper turning blue
Chemical Reaction Notes
What is the coefficient of bromine in the
equation 2Al(s) 3Br2(l) ? 2AlBr3(s)? A. 1
B. 2 C. 3 D. 6
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