1. Significant Figure Notes With scientific notation too

2. Sig Figs Rule 1: “Non-Zeroes Count” NON-ZERO numbers ARE significant How many sig figs? 3.1428 ____3.14 ____469 ____

3. Sig Figs Rule 2: “Sandwiched Zeroes Count” All zeros BETWEEN significant digits ARE significant. How many sig figs? 7.053 x 10 3 ____70501 ____ 3020 ____ Only count the numbers to the left of the multiplication sign!

4. Sig Figs Rule 3: “Lefty Zeroes Don’t Count” Zeroes to the LEFT of significant figures are NOT significant. How many sig figs? 0.0056 ____0.07089 ____0.000001 ____

5. Sig Figs Rule 4: “Righty Zeroes…Sometimes Count” Zeroes on the far right ARE significant if the number contains a DECIMAL POINT Zeroes on the far right are NOT significant if the number has NO decimal point How many sig figs? 4.300 x 10 -4 ____ 200 ____ 0.010050 ____78020 ____

6. Practice We Do: 3.705 mL _____ 0.0052 g _____ 82,000 s _____ 6.19 x 10 1 years ______ Next, try the “You Do” problems on your own!!

7. Scientific Notation I Do: 3250000000  0.00034 

8. Scientific Notation I Do: 3250000000  0.00034  We Do: 0.025  55, 000  Now try the “You Do” problems on your own!

9. Scientific Notation IN REVERSE! Make sure you know how to go in both directions! 4.78 x 10 -2  5.50 x 10 4  This can also be done with a calculator!

10. Addition/Subtraction When you add or subtract numbers with different precision, you must round your final answer to the least precise number place. Ex. 150.0 g + 0.507 g 150.507  150.5 g

11. Addition/Subtraction When you add or subtract numbers with different precision, you must round your final answer to the least precise number place. We Do: What is the total mass of 33.0 g of KCl and 56.50 g of H 2 O 2 ? Now try the “You Do!”

12. Multiplication/Division When you multiply or divide numbers with different precision, you must round your final answer to the least number of sig figs. We Do: What is the density (D = m/V) of a 87.45 g metal sample with a volume of 2.0 cm 3 ? Now try the “You Do!”