1. Chapter 2, Section 5 Mass and Volume

2. August 30, 2011 HW: None 2.3 Quiz Honors Requirements Choose Chapter/Section for presentation – Choose from Ch. 2.6-2.9, Ch. 6 (skip 6.5 and 6.8), Ch. 1 Find current event

3. 2.3 Quiz Differentiate between solutions, suspensions, and colloids FilterLaser BeamExample Solution Suspension Colloid

4. 2.3 Quiz Differentiate between solutions, suspensions, and colloids FilterLaser BeamExample SolutionPass throughPass straight through NaCl in water SuspensionLiquid will pass thru, larger particles caught in filter paper Stops laser beamSoil in water ColloidPass throughScatters/spreads out Milk

5. August 30, 2011 HW: 2.5 CTG, pg 142, #1-9, 11(Due Friday) LO – Determine density of liquids and solids – Correctly use significant figures SC – Determine the densities of various liquid and solid materials – Make measurements in the lab to the precision of the instruments used – Learn the difference between accuracy and precision in experimental measurements – Use density measurements to determine the identity of a material – Locate sources of the variation in the class’s results Do Now – Write LO and SC on new left side page – WDYS/WDYT-pg 134 Agenda – Do Now – Investigate – Summary

6. Investigate Part A-pg 134-136 Set up notebook for #1-5, OK with teacher Complete #1-5 Graph data as a class (6a) Answer questions 6b-f in your notebook using your graph Complete #7-9 Show teacher your calculations

7. Investigate Part B: pg. 136-7 Set up notebook for #1, 3-6. Ok with teacher Complete #1, 3-6 using the method shown below Calculate Density (#6) using Density=mass/volume

8. Summary Why do some objects float while other sink? – Be sure to use the terms mass, volume, and density

9. September 6, 2011 HW: 2.5 CTG, pg 142, #1-9, 11 (Due Wed) LO – Determine density of liquids and solids – Correctly use significant figures SC – Determine the densities of various liquid and solid materials – Make measurements in the lab to the precision of the instruments used – Learn the difference between accuracy and precision in experimental measurements – Use density measurements to determine the identity of a material – Locate sources of the variation in the class’s results Do Now – Explain the layers in the density column. – How is it possible for giant cruise ships and tankers made of steel to float in the ocean? Explain using density. I know we already did this, but I want to see if you understand! Agenda – Do Now – Chem Talk – Summary

10. Part C-Teacher Demo http://link.brightcove.com/services/player/bc pid34762914001?bckey=AQ~~,AAAAB_wnNRk ~,WN9MweAQd_tBaI99JKgDAcW3bUx7peWv &bctid=84449964001 http://link.brightcove.com/services/player/bc pid34762914001?bckey=AQ~~,AAAAB_wnNRk ~,WN9MweAQd_tBaI99JKgDAcW3bUx7peWv &bctid=84449964001

11. Chem Talk What is density? What is the equation for Density? A measurement of mass per unit of volume Density=mass/volume D M V D=

12. Chem Talk When will objects sink? When will objects float? When will objects neither sink or float? When the object is MORE dense than the liquid, it will sink When the object is LESS dense than the liquid, it will float on top Objects with the SAME density will suspend in the middle of the liquid.

13. Chem Talk How can you measure the volume of a solid? Volume=LxWxH Volume of an irregular solid: Use water displacement method

14. Chem Talk Significant Figures: Measurement should be the same as the smallest division on your measurement instrument.

15. Chem Talk Significant Figures… Calculations: – Adding or subtracting: Arrange the numbers so the decimals line up. Complete the addition or subtraction. Draw a vertical line to mark the end of your least precise number The answer should have the same number of decimal places as the least precise number. 12.76 + 3.875 16.635 Answer= 16.64

16. Chem Talk Significant Figures… – Multiplying and Dividing The result should have NO MORE Sig Figs than the factor with the LEAST amount of significant figures. Counting sig figs – 735=3 sig figs – 2008=4 sig figs (zeros count) – 00.0076=2 sig figs (zeros on the left don’t count) – 820.00=5 sig figs (zeros on the right count IF there is a DECIMAL point!) – 230=2 sig figs (no decimal)

17. Significant Figure Rules There are three rules on determining how many significant figures are in a number: – Non-zero digits are always significant. – Any zeros between two significant digits are significant. – A final zero or trailing zeros in the decimal portion ONLY are significant.

18. Practice http://www.chem.sc.ed u/faculty/morgan/resou rces/sigfigs/index.html http://www.chem.sc.ed u/faculty/morgan/resou rces/sigfigs/index.html Sig Fig Practice 1 Sig Fig Practice 2 Density Practice

19. Summary LO and SC reflection

20. Relay! Get out HW: packet and 2.5 CTG Density and Sig Fig Relay 2.5 Quiz

21. RELAY Get a calculator There are three rules on determining how many significant figures are in a number: – Non-zero digits are always significant. – Any zeros between two significant digits are significant. – A final zero or trailing zeros in the decimal portion ONLY are significant. D= D M V

22. RELAY! Get a Calculator and be ready for your density relay!