Significant Figures

Which is more precise? .00700 or 7.00

First we need to understand significant figures A helpful trick involves a little geography… -Note where the Atlantic and Pacific Oceans are...

If the decimal is Present, count from the Pacific side, starting with the first non-zero How many Sig figs are in each of the following numbers? 9.083 9.9990 0.1830 .00700 Pacific Ocean 4 sig figs 5 sig figs 3 sig figs

If the decimal is Absent, start counting digits from the Atlantic side, starting with the first non-zero digit How many Sig figs are in each of the following numbers? 9000 99099 183 7001 1 sig figs 5 sig figs 3 sig figs 4 sig figs Atlantic Ocean

So which is more Precise .00700 or 7.00? Hint: Which has more Sig Fig’s It’s the same! Both have 3 Sig figs It may help to think of it with units .00700 Km is the same as 7.00 m

How many Sig Figs are in... .900 900 1001 .001 3 Sig figs 1 Sig Fig 4 Sig Fig

How do we know how many sig fig’s to use when we are measuring? You can go one place beyond the instrument. For example: This ruler marks every .001 meters We can go to .0001 meters

What happens when you Add, Subtract, multiply and Divide Sig Figs?

Addition and Subtraction of Sig Figs... Count the number of sig figs in the decimal portion ONLY Add or subtract Round to the LEAST number of decimal places found in the problem

8.2087 mL +2.430 mL +0.09 mL 5.157 m +2.009 m +3 m 10.7287 mL 10.73 mL 10.166 m 10 m

Multiplication and Division A number is no more precise than the least precise value (a chain is only as strong as weakest link) Determine the number of Sig Figs for each number in the problem What is the least amount of Sig Figs? This is how many sig figs your answer should have

7.750 g 5.4 mL 23.587g 32.5mL = 1.435185185 g/mL = 1.4 g/mL =.7257538462 g/mL =.726g/mL