Significant Figures

Why care? Allows us to be accurate with the information we actually have.

Rules All nonzero numbers are significant. Ex: 432 = 3 sig figs 0’s between nonzero numbers are significant Ex: 401 = 3 sig figs Trailing zeros are not significant unless there is a decimal point. Ex: 4000 = 1 sig fig Ex: 400.0 = 4 sig figs Leading zeros are not significant. Ex: 0.000302 = sig figs

Multiplying and Dividing Measurements The answer will have the same number of sig figs as the measurement with the least amount of sig figs. Ex: 5.00 g / 2.5 mL = 2.0 g/mL 5.00 g / 2.500 mL = 2.00 g/mL

Adding and Subtracting Measurements The answer will have the same amount of numbers after the decimal as the measurement with the least amount of numbers after the decimal. Ex: 4.38 g + 4.2 g = 8.58 g = 8.6 g 8.73 mL – 2.224 mL = 6.51 mL