NAME:________________________________
DATE:_____________
PERIOD:____
Significant Figures Notes
MEASUREMENT
Some error or ____________________ always exists in any measurement. This is due to
_____________________________________________________________________________________
All measurements in science should have ______ uncertain or __________________ digit. It is always
the _________ number in a measurement.
Q: What would be an appropriate measurement for the water in the graduated cylinder to the left?
Explain why 44 mL is incorrect.
A:___________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
Q: What would be an appropriate measurement for the pencil shown to the right?
8.235 cm is incorrect.
Explain why
A:___________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
Practice Problems
_______ cm
_______ mL
_______ cm
#: _____
Significant Figures Notes
SIGNIFICANT FIGURE RULES
1.
Any _________________ number is _________________significant.
a. 28.49 has _____ significant figures.
2. Any zero(s) ___________________________________________numbers is ALWAYS significant.
a. 505.7009 has _____ significant figures.
3. Any _________________ zero(s) (leftmost zeros), is _________________ significant.
a. 0.00896 has _____ significant figures.
4. Any zero(s) at the __________________________________ AND to the _________________
of a decimal is ALWAYS significant.
a. 943.8900 has _____ significant figures.
5. Any zero at the __________________________________ AND to the _________________ of a
decimal is NEVER significant UNLESS there is an obvious decimal.
a. 980 has _____ significant figures.
b. 980. has _____ significant figures.
Summary of Significant Figure Rules:
ALL numbers are considered significant EXCEPT:


PRACTICE PROBLEMS
How many significant figures are in the following measurements?
1. 15.39
5. 0.000239
9. 3.982 x 106
2. 9.078003
6. 0.00023900
10. 1.00040
3. 4.0800
7. 48000.
11. 190
4. 2345.8736
8. 48000
12. 1.50 x 103
Significant Figures Notes
MULTIPLYING AND DIVIDING WITH SIGNIFICANT FIGURES
The final answer should be rounded to the same number of ___________________________________
as the measurement with the ____________ number of significant figures in the problem.
a. 4.0 x 5 =
b. 4.00 x 5.0 =
c. 4.000 x 5.00 =
ADDING AND SUBTRACTING WITH SIGNIFICANT FIGURES
The final answer should be rounded to the same number of ___________________________________
as the measurement with the ____________ number of decimal places in the problem.
a. 4.4 + 5 =
b. 4.02 + 5.0 =
c. 4.006 + 5.00 =
CONVERSION FACTORS
Conversion factors are ___________ numbers, and therefore have an __________________ number of
significant figures.
Q: How should you round your answer when you are doing a problem that involves conversion factors?
A: __________________________________________________________________________________
__________________________________________________________________________________
Significant Figures Notes
PRACTICE PROBLEMS
Solve the following mathematical problems so that the answers have the appropriate number of
significant figures and correct units:
1. 334.54 grams + 198 grams =
2. 34.1 grams / 1.1 mL =
3. 2.11 x 103 joules / 34 seconds =
4. 0.0010 m – 0.11 m =
5. 349 cm + 1.10 cm + 100 cm =
6. 450 meters / 114 seconds =
7. 298.01 kilograms + 34.112 kilograms =
8. 84 m/s x 31.221 s =
9. Convert 98.2 cm  feet
10. Convert 2.0 weeks  hours
(2.54 cm = 1 in. and 12 in. = 1 ft.)
(7 days = 1 wk. and 24 hr. = 1 day)