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

2. 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

3. What is the difference between the three rulers?

4. What is the difference between these balances?

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

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

9. 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

10. 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. = cm

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

12. 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.

13. 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.

14. Practice Exercises 26.5862 L + 0.17 L 9.1 g – 4.682 g
7.1 dm x dm
6.54 g / mL
A L
B g
C. 16 dm2
D g/mL

15. Significant Figures

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