1. Daily Oral Review (DOR)  What is your favorite school subject?  What should I know about you so I can help you succeed in chemistry?

3. Scientific Measurements SI Units Significant Figures ALWAYS WRITE YOUR UNITS ON YOUR ANSWER !!!!----units provide meaning to numbers.

4. Significant Figures The number of digits in a scientific measurement known with certainty and one estimated or uncertain digit. Method of reporting scientific measurements and calculations.

5. Significant Figure Basic Rules 1. All numbers that are NOT zeroes are significant Ex. 211, 345 2. All zeroes BETWEEN 2 significant figures are significant. Ex. 2003, 1203 3. All zeros that are FINAL and PAST a decimal are significant. Ex..00020

6. Examples 1) 567 2) 9001 3) 10.020 4) 200

7. Significant Figures: Adding/Subtracting # of digits to RIGHT of decimal = # of digits RIGHT of decimal from number with the LEAST digits. Ex.1 67.14 kg + 8.2 kg = 75.3 kg Ex. 2 101.23 g – 90.614 g = 10.62 g

8. Significant Figures: Multiplying/Dividing # of significant figures = # of significant figures in number with LEAST significant figures. Ex. 1 12.1 / 3.1 = 3.870967742 ~ 3.9 Ex. 2 45.67 * 1.23 = 56.1741 ~ 56.2

9. Rounding Guidelines Rules of “5” > 5, round UP (ex. 56.77---- 56.8) < 5, SAME/no change (ex. 56.74 ----- 56.7)

10. Significant Figure Practice 1) 9006) 804.5 2) 10207) 0.0144030 3) 0.00020 8) 1002 4) 1000349) 0.000625000 5)0.0001001010) 17.982 g / 4.13 cm 3 = 11) 12.4 + 1.345 = 12) 2.0 * 4.35 =