1. Significant figures A significant figure represents an actual measurement A measurement of all the digits known with certainty, plus one that is estimated or uncertain

2. All non-zero digits are significant 325 ml 1.325 ml Zeros appearing between non-zero digits are significant 40.7 L 32006m Zeros appearing in front of non-zeros are not significant 0.0572 m 2 0.0002 g Zeros at the end of a number with a decimal are significant 97.00 kg 1200.00 g Numbers without decimals usually have non- significant zeros 3400 g 4000 ml

3. 30040 g 0.663 kg 20.05 ml 1500. m 0.0008 cm 640 cm 3 200.0 ml 0.5200g 1.005 kg 10000L 120 g/L

4. least accurate You can calculate any measurement as accurately as the least accurate measurement that was used in the calculation. Density = mass /volume 11.079g/12.7m = a.47.0 m/2.2s b.140 x 35cm c.5.88kg /200 m 3 d.0.050 m 2 x 0.042 m

5. Exact numbers do not have to be considered when rounding For example conversion factors or counted numbers If I have 10 test tubes and I put 2.56 g of sugar in each I will have _____ g of sugar (no need for rounding)

6. Express the following in scientific notation, with the correct number of sig. figs. and correct units 4.70 m/2.2 s 140 x 35 cm 5.88 kg/200 m 3 0. 0050 m 2 x 0.042 m 33.00 cm 2 x 2.70 cm 35000kJ /0.250 mm

7. Perform the following computations and express the results in sci. notation with the correct # of sig. figs. 1.547 x 10 -1 / 2.36 x 10 -4 3.89 x 10 4 mm x 4.7 x 10 2 mm 2 9.57 x 10 3 kg / 3.823 x 10 -1 m 2 8.331 x 10 3 km / 1.970 x 10 2 s 9.364 x 10 2 m x 3.8254 x 10 3 m x 9.01 x 10 -1 m 1.36 x 10 7 cm – 1.010 x 10 6 cm 3.610 x 10 -2 g – 3.6 x 10 -3 g