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