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

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

30040 g kg ml m cm 640 cm ml g kg 10000L 120 g/L

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

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)

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 m 2 x m cm 2 x 2.70 cm 35000kJ /0.250 mm

Perform the following computations and express the results in sci. notation with the correct # of sig. figs x / 2.36 x x 10 4 mm x 4.7 x 10 2 mm x 10 3 kg / x m x 10 3 km / x 10 2 s x 10 2 m x x 10 3 m x 9.01 x m 1.36 x 10 7 cm – x 10 6 cm x g – 3.6 x g