chem unit 1

Sig Figs

  • Nonzero integers always count

  • Leading zeros do not count

  • Sandwich zeros count

  • Trailing zeros don’t count unless it has a decimal

  • Exact numbers do not limit the number of sig figs in the answer

Multiplication/Division

  • Use the same # of sig figs in the result as the number w the fewest sig figs

Addition/Subtraction

  • The decimal places in the result must be the number of decimal places in the one with the fewest decimal places

  • The answer should have the same number of trailing zeros as the measurement with the most trailing zeros

Dimensional analysis

  • Convert to base

  • 1 mole = 6.02 x 10^23

  • Kangaroos Hopped Down Black Dark Caves, Making Mysterious Noises

Balancing Chemical Reactions

  • Cats Bring Rice Dishes

    • Count atoms of each element

    • Balance one element at a time

    • Revisit other elements

    • Double-check!

  • Reactants are on the left side

  • Products are on the right side

  • Coefficients are used to balance the equation

  • Coefficients also represent the number of moles

    • Balance the equation so the atom counts match

    • Check your work and reduce coefficients to the lowest whole numbers

Acids and Bases

  • Blue to red for acids

  • Red to blue for bases

  • Remember acids turn angry

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