Significant Figures and Scientific Notation Assignment: WS Sig Figs and Scientific Notation

Significant Figures tell us where to round calculated values based on Measurements Numbers recorded in a measurement. All the certain numbers plus one estimated number

What is the difference between the three rulers?

What is the difference between these balances?

Significant Figures Rules for Counting Significant Figures Nonzero numbers always count as significant figures. Ex. 1457 g 4 significant figures

Significant Figures Rules for Counting Significant Figures Zeros Leading zeros - never count 0.0025 m Sandwich zeros - always count 1.008 L Trailing zeros - count only if the number is written with a decimal point 100 g 100. g 120.0 g 2 significant figures 4 significant figures 1 significant figure 3 significant figures 4 significant figures

Atlantic Pacific Rule: If a decimal is Present, begin counting from the Pacific side at the first non zero number. If the decimal is Absent, begin counting from the Atlantic side at the first non zero number. Atlantic Ocean Pacific Ocean

Significant Figures Rules for Counting Significant Figures Exact numbers - unlimited significant figures Not obtained by measurement Determined by counting 3 apples Determined by definition 1 in. = 2.54 cm

Significant Figures - Practice Examples: How many Sig Figs? 304.2 cm 0.0098 s 140 K 2.001040 kg 28.0

Significant Figures Rules for Addition and Subtraction The number of significant figures in the result is the same as in the measurement with the smallest number of decimal places.

Significant Figures Rules for Multiplication and Division The number of significant figures in the result is the same as in the measurement with the smallest number of significant figures.

Practice Exercises 26.5862 L + 0.17 L 9.1 g – 4.682 g 7.1 dm x 2.2654 dm 6.54 g / 86.5542 mL A. 26.76 L B. 4.4 g C. 16 dm2 D. 0.0756 g/mL

Significant Figures

Rounding Practice (round off to # in parentheses) 101023 cm (3) 2534 kg (2) 56.291 s (3) 145 K (2)