1. Warm Up 8-23-17 Agenda Homework Notes Unit 1-5 Lab Density
Provide 2 examples
Matter
Compound
Homogeneous
Heterogeneous
Provide 2 examples
Diet coke vs regular coke density demo.
Agenda
Notes Unit 1-5
Lab Density
Homework
Aug 29 - Notebook check Unit 1
Aug 29 - Online HW Unit 1
Aug 30 - Test Unit 1

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/cm3
The density of an object is the same no matter its volume
Talk about Archimedes' principle and buoyance ship
-Density is also a physical property of matter that can be used to identify substances (stuff per space)

6. Density Example Problems
1. What is the density of an object that weights 2200g and has a volume of 100cm3?
2. Gold’s density is 19.3g/cm3 If a gold bar has mass of 150g what is its volume?
3. Find the density of this cube.
Mass = 30g
2.2kg is about the weight of a text book

7. Rounding Measurements
Accuracy- how close a measurement is to the actual value
Actual penny diameter is cm Due to equipment error

8. Rounding Measurements
Precision- how frequently you get the same measurement when measuring in the same way
Due to human error
Playing darts

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
Brass = copper + zinc
Bronze = 12% tin + some other metals

13. Assignments
Summary - Describe a way to measure the volume of a gold necklace.
Lab due next class

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 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 has 2 sig figs e.g

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 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 has 1 sig fig, but 30.0 has 3 sig figs

18. Sig Fig Practice Determine the number of sig figs in each value 4658.2
4006
0065
1.0065
3.0
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
12 x 4 = ?
1.0 x 623 = ?

20. Sig Figs in Calculations
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
= ?
9.899 – 2.23 = ?