1. Significant Figures & Scientific Notation
Unit 1
Significant Figures & Scientific Notation

2. Significant Figures – The accuracy of a measurement.
Rule # 1
All Non-zero numbers are significant.
235 mol mL kg
(3 Sig figs) (2 Sig figs) (5 Sig figs)

3. Captive zeros are significant – zeros between non-zero numbers.
Rule # 2
Captive zeros are significant – zeros between non-zero numbers.
mm s g
(6 sig figs) (5 sig figs) (3 sig figs)

4. Rule # 3
Zeros after nonzero numbers with a decimal present are significant.
59.00 g kL m
(4 Sig figs) (2 Sig figs) (5 Sig figs)

5. Rule # 4
Zeros that act as place holders are not significant.
-Zeros to the left of nonzero numbers or to the right of nonzero number when NO decimal is present.
100 L mL Pa
(1 Sig figs) (2 Sig figs) (3 Sig figs)

6. Multiplication and Division
Perform calculation
Round the answer to the same number of significant figures as the least amount of sig figs in the problem.
1.) 3.2 x 11.0 = 35.2
= 35
2.) 7456 x 3.56 =
= 26500

7. Practice:
2.2 x 3.12 =
x 3.10 =
3. 96  =

8. Scientific Notation There are atoms in 12 grams of carbon. The mass of a proton is kg. Who wants to write all those #’s??? Scientific Notation is a short hand way to write very large or very small #s.

9. How to write #’s in Scientific Notation
1- Move the decimal so that only one sig fig is to the left of it
2- Remove all non significant zeros
3- Multiply the rest of the # by 10, and raise it to the power equal to the # of times you moved the decimal (1.0 x 10x)
4- The way you move the decimal depends on whether it is a positive or negative power
Decimal moves right = Negative power
(the # was less than 1.0)
Decimal moves left = Positive power
(the # was greater than 1.0)

10. Scientific Notation Practice