Happy Birthday to Niels Bohr (1885)

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Presentation transcript:

Happy Birthday to Niels Bohr (1885) Reading: Chapter 2 sections 5-8

Sig. Figs. in Calculations Two rules: #1) Multiplication and Division The value in the calculation that has the FEWEST number of sig. figs. determines the number of sig. figs. in your answer.

Calculations with Sig. Figs. Multiplication and division The value in the calculation that has the FEWEST number of sig. figs. determines the number of sig. figs. in your answer. 1.5 x 7.3254 = 1 .9891 = 11 2 s.f. 5 s.f. 6.127 x (2.67030x10-5) = 0.000163 6 09 = 0.0001636 4 s.f. 6 s.f.

Sig. Figs. in Calculations Two rules: #1) Multiplication and Division The value in the calculation that has the FEWEST number of sig. figs. determines the number of sig. figs. in your answer.

Calculations with Sig. Figs. 927.381 / 456.0 = 2.03 3 730263 = 2.034 6 s.f. 4 s.f. 0.00159 / 2 = 0.000 7 95 = 0.0008 3 s.f. 1 s.f. 6 s.f. 3 s.f. = 18 8 99522.37 = 1.889952237x107 4 s.f. = 1.89x107

Some Practice 890.00 x 112.3 78132/2.50 0.0120 x 48.15 x 0.0087 500 x 0.000230012 99950 or 9.995x104 31300 or 3.13x104 0.0050 2.5x10-8 1.9x106 0.1

Sig. Figs. in Calculations Two rules: #1) Multiplication and Division: The value in the calculation that has the FEWEST number of sig. figs. determines the number of sig. figs. in your answer. #2) Addition and Subtraction: The value in the calculation that has the FEWEST decimal spots determines the number of decimal spots in your answer.

Adding and subtracting with sig. figs. 0.0025647 + 0.000321 7 decimal places 6 decimal places 0.0025647 0.0025647 +0.000321_ +0.000321_ 0.0028857 0.0028857 = 0.002886 answer can only be precise to the 6th decimal place

Adding and subtracting with sig. figs. 394.0150 + 0.0074121 4 decimal places 7 decimal places 394.0150 394.0150 + 0.0074121 + 0.0074121 394.0224121 394.0224121 = 394.0224 answer can only have 4 decimal places

Adding and subtracting with sig. figs. 0.01 – 0.006125 2 decimal places 6 decimal places 0.01 0.01 – 0.006125 – 0.006125 0.003875 0.003875 = 0.00 answer can only be precise to the 2nd decimal place

Adding and subtracting with sig. figs. 682377 + 5922.60 no decimal places 2 decimal places 682377 682377 + 5922.60 + 5922.60 688299.60 688299.60 = 688300 6.88300x105 answer can only be precise to the ones place

Some More Practice 23.67 – 75 5502.8 + 24 + 0.01 0.109 + 0.09 – 0.955 20.4 + 1.322 + 78 61690 - 0.096 -51 5527 -0.76 100. 61690 or 6.169x104