1. WARM UP8-25-15 Agenda Notes Unit 1-5 Lab Density Homework Aug 26 - Notebook check Unit 1 Aug 29 - Online HW Unit 1 Aug 30 - Test Unit 1 1. Provide 2 examples Compound Matter Homogeneous Heterogeneous

2. Unit 1-5 Density and Rounding Measurements

3. Properties of Matter Chemical Properties: A property of matter that let it react with another chemical Chemical properties can only be identified by trying to cause a chemical change

4. Properties of Matter Physical Property: A property that can be determined without changing the nature of the substance Example: sugar’s physical properties would include that it is solid, white More examples: State of matter Melting points Boiling point Mass and volume Density

5. Properties of Matter Density = mass ÷ volume Unit is g/cm 3 The density of an object is the same no matter its volume

6. Density Example Problems 1. What is the density of an object that weights 2200g and has a volume of 100cm 3 ? 2. Gold’s density is 19.3g/cm 3 If a gold bar has mass of 150g what is its volume? 3. Find the density of this cube. Mass = 30g

7. Rounding Measurements Accuracy- how close a measurement is to the actual value

8. Rounding Measurements Precision- how frequently you get the same measurement when measuring in the same way

9. Rounding Measurements Round the following numbers: 5.76 to the nearest tenths 453 to the nearest tens 3.685 to the nearest hundredths

10. Scientific Notation Used to make numbers easier to deal with and to keep track of zeros Only one number before decimal! Using calculators with scientific notation: Number * 10 ^ (exponent) Number EE (exponent)

11. Scientific Notation Examples

12. Density Lab Follow the lab procedure to find the volume of pennies and metal cylinders Find the unknown materials used to make the cylinder objects and the cubes by finding its density

13. Assignments Summary - Describe a way to measure the volume of a gold necklace.

14. EXTRA NOTES NOT APPLICABLE

15. Significant Figures Significant figures are used to indicate the preciseness of measurements - Significant figures consist of all the digits known with certainty as well as one estimated, or uncertain digit - Use for rounding answers

16. Rules for Determining Significant Figures 1. Nonzero digits are always significant e.g. 643.5 has 4 sig figs 2. Zeros between nonzero digits are significant e.g. 909 has 3 sig figs 3. Zeros in front of non zero digits are not significant e.g. 0.00034 has 2 sig figs e.g. 00063

17. Rules for Determining Significant Figures 4. Zeros both at the end of a number and to the right of a decimal point are significant e.g. 9.00 has 3 sig figs 5. Assume zero to the right of a number but to the left of the decimal point is not significant e.g. 4000 has 1 sig fig, but 30.0 has 3 sig figs

18. Sig Fig Practice Determine the number of sig figs in each value a) 4658.2 b) 4006 c) 0.000265 d) 0065 e) 1.0065 f) 3.0 g) 700

19. Sig Figs in Calculations When multiplying and dividing, round your answer to the least number of sig figs in the equation Multiplying and Dividing a) 12 x 4 = ? b) 1.0 x 623 = ?

20. When adding and subtracting, round your answer to the least number of decimal places in any of the data you are given. Adding and Subtracting a) 3.11 + 1.2 = ? b) 9.899 – 2.23 = ? Sig Figs in Calculations