2. Scientific Notation Scientific Notation: a method for __________________________________________. Moving the decimal to the _______________exponent, to the _________________________________________. Ex. 0.00527g = 5.27 x 10 -3 g 52700000 m = 5.27 x 10 7 m 3.25 x 10 -6 cm 3 = 0.00000325 cm 3 3.25 x 10 4 cm 3 = 32500cm 3 2-2

3. Scientific Notation Practice: 1) 0.000060731 ml = 2) 2.970 x 10 -5 mg = 3) 546901000 kg = 4) 6.3 x 10 7 s = 2-3

4. Rounding Atomic Masses Rounding Atomic Masses: we will be rounding the atomic masses off the periodic table to the __________________________________________ Ex. C = 12.011 g/mol = 12.01 g/mol Bi = 208.98038 g/mol = 208.98 g/mol K = 39.0983 g/mol = 39.10 g/mol

5. Rounding Atomic Masses Practice: 5) N = 14.00674 g/mol = 6) Si = 28.0855 g/mol = 7) O = 15.9994 g/mol = 8) Ar = 39.948 g/mol = 2-5

6. Significant Figures Non zeros are always ____________________. Zeros _____________________are significant. Leading and trailing zeros ___________________________________. Atlantic/Pacific Rule: Pacific: Point Present, start from the left, first nonzero and everything after is significant Atlantic: Point Absent, start from the right, first nonzero and everything after is significant.

7. Significant Figures Ex. 1200 = 2 sig figs0.003 = 1 sig fig 1.200 = 4 sig figs0.0030 = 2 sig figs Practice: 9) 1.2650 = 10) 325000 = 11) 1.280 x 10 -1 = 12) 31006 = 2-7

8. Significant Figures Rounding Calculations According to Sig Figs Addition and Subtraction: Round answers to the _____________________________________________: Ex. 2.26.9801 + 5.67 - 4.21 7.87 = 7.92.7701 = 2.77 2-8

9. Significant Figures Practice: 13) 4.71 - 1.1 14) 5.367 + 1.2 2-9

10. Significant Figures Multiplication and Division: Round answers to the _______________________________________________ ________________________________________: Ex. 2.60 x 300 = 780 = 800 52.31 x 2600 = 136006 = 140000 2000000 ÷ 5.63 = 355239.7869 = 4000000 78 ÷ 6 =13 = 10 2-10

11. Significant Figures Practice: 15) 240. ÷ 6.0 = 16) 365 ÷ 5 = 17) 32 ÷ 3 = 18) 32 x 3.0 = 2-11

12. Dimensional Analysis Used to convert between units. Take an equivalent (12 in. = 1 ft.) and make it into a __________________: 1 ft. or 12 in. 12 in. 1 ft. Use conversion factors to convert between units. _______________________________________________ and multiply by the conversion factor with _____________________________________________. (so they cancel) 2-12

13. Dimensional Analysis Ex. 5.36 ft. = ? in. 5.36 ft. x 12 in. = 64.32 in. = 64.3 in. 1 ft. 32 in. = ? ft. 32 in. x 1 ft. = 2.666 ft. = 2.7 ft. 12 in. 12-13

14. Dimensional Analysis Ex. 3.26 in. = ? cm 3.26 in. x 1 cm= 8.280416561 cm = 8.28 cm 0.3970 in. 25 g = ? kg just use your handout, move your decimal 3 places to the left 25 g = 0.025 kg 5.69 oz. = ? g 5.69 oz. x 28.3 g= 161.027 g = 161 g 1 oz.

15. Dimensional Analysis Ex. 1 year = ? S 1 year x 365 days x 24 hours x 60 min. X 60 s = 1 yr. 1 day 1 hr. 1 min. = 31536000 s = 30000000 s 12-15