OBJECTIVE: To learn to determine the number of significant figures in a calculated result.
Here we will learn to determine the number of significant figures in a calculation.
Rules for Significant Figures
1. Nonzero integers are always significant
- 1, 2, 3, 4, 5, 6, 7, 8, 9
2. Three classes of zeros
a) Leading zeros are never counted as significant
3. Exact numbers
Here we will learn to determine the number of significant figures in a calculation.
Rules for Significant Figures
1. Nonzero integers are always significant
- 1, 2, 3, 4, 5, 6, 7, 8, 9
- how many significant figures are in this measurement 1.234 cm
- Answer: 4
2. Three classes of zeros
a) Leading zeros are never counted as significant
- Leading zeros are zeros that precedes all of the nonzero digits
- 0.0025mi. So how many significant figures are there in the measurement?
- Answer: 2 because the three zeros do not count since the are before the nonzero integers
- Captive zeros are zeros that fall between nonzero digits
- 10.01 m/s. So how many significant figures are there in the measurement?
- Answer: 4 because the zeros is between two nonzero integers (1 and 4)
- Trailing zeros are zeros at the right end of the number
- 1000. m; how many significant figures are in the measurement?
- Answer: 4 because of the decimal point behind the zero
3. Exact numbers
- calculation involved with counting has unlimited significant figures.
- Example: 10 people, 100 dollar, 3 apples, 8 molecules, and etc.
- Such numbers are called exact numbers. They can be assumed to have an unlimited number of significant figures.
Examples
How many significant figures are in the values shown below?
Answer
Video
How many significant figures are in the values shown below?
- 0.0101mg
- 123.020 mL
- 0.0100034 L
- 8182011. cal
Answer
- 3 - 0.0101mg
- 6 - 123.020 mL
- 6 - 0.0100034 L
- 7 - 8182011. cal
Video