Notes Significant Figures!

Rules for Sig Figs!! 1. All non-zero digits are significant. Example: 2.17 - 3894.6 -

Rules for Sig Figs!! 2. Leading zeros (zeros to the left) are never significant. Example: 0.003 - 0.0000045 –

Rules for Sig Figs!! 3. Captive zeros (zeros in the middle) are always significant. Example: 205 – 20005 –

Rules for Sig Figs!! 4. Trailing zeros (zeros at the end) are sometimes significant: a) They are significant if the number contains a decimal point. Example: 155.0 - 0.450 –

Rules for Sig Figs!! 4. Trailing zeros (zeros at the end) are sometimes significant: b) They are not sig. if the number does not contain a decimal point. Example: 1550 – 45000 –

Summary 0.000424000600 (Trailing) (Leading)Never sig. (Captive) Always sig. (Trailing) Sometimes sig. (decimal=sig.) (Leading)Never sig.

Practice Makes Perfect! 4.59 3.00 20,202 0.0050 43,000 1.09 x 104

Significant Figures! (In calculations) Notes Significant Figures! (In calculations)

LOOK at the decimal places! Sig Figs in Calculations Addition and Subtraction: LOOK at the decimal places! The answer is rounded to the same number of decimal places as the number used in the calculation with the least decimal places. Ex: 5.7 7. 12 162.1 g + 2.11 –1.345 38.78 g +1.554 g

Sig Figs in Calculations Multiplication and Division: LOOK at the total number of sig figs! The answer is rounded to the same number of sig. figs. as the number used in the calculation with the least significant figures 0.0561 Ex: 17.85/2.13 = x 0.030 62 g/1.62 cm =

Significant Figures! (in Scientific Notation) Notes Significant Figures! (in Scientific Notation)

Number of sig figs remain the same. Sig Figs in Scientific Notation Converting from Scientific Notation: Number of sig figs remain the same. Ex: Convert from scientific notation: 9.9 x 103 = 1.89 x 10-4 =

Sig Figs in Scientific Notation Converting to Scientific Notation: The # of sig figs stays the same, but there is only one sig fig in front of the decimal. Ex: Convert to scientific notation: 1100000 = 749.3 =