Do Now: 3/2/16 HW: Physical/Chemical Changes handout. Current Events #13-16 Friday. Do Now: 3/2/16 Turn in the Candy Bar Lab. Liquids of different densities will separate when combined together. Match the density of each layer of liquid in the handout. **Check out the sample on my desk to help you**

Highest density is on bottom 0.3g/mL 0.5g/mL 0.9g/mL 1.0g/mL 4.5g/mL 7.8g/mL 13.6g/mL Highest density is on bottom 2

More Density Review Turn to lab page 36.

Density Practice – pg 36 What is the density of water? (include units) What are two different units you can use to represent density? Density is a physical property of a substance, true or false? The density of water is 1.0 g/cm3 Dry measurement units are g/cm3 Liquid measurement units are g/ml True

Density Practice 4. Billy’s sample of gold has a density of 19.3 g/mL. If the sample were cut into three pieces, what would the density of each new piece be? D = M Mass 116g 19.3 g/ml V Volume 6ml

6. What is the relationship between a cm3 and a mL? 4 5 0.2 2000 D = M V V = M D Density Practice Fill in the chart 6. What is the relationship between a cm3 and a mL? Substance Volume (mL) Mass (g) Density (g/ML) A 5 20 B 3 15 C 10 50 D 100 4 5 0.2 2000 M=V X D 1 cm3 = 1 ml

Density Practice: Percent Under Water Page 38 When an object floats in water, we can use its density to determine the percent of the object that is below the water line. This works for objects that are less than 1.0 g/cm3 Anything greater will sink and 100% of the object will be under water. *Remember: Density of water is always 1.0 g/cm3 or 1.0 g/mL

Density Practice: Percent Under Water 1a. Example: a cube with a density of 0.5 g/cm3 floating in water might look like the picture below: 1b. To figure out percentage under water: Take the density and convert to a percentage. Note: You see half of the object under water. So, 50% of the object is under water. Density = 0.7 g/cm3 0.7 = 7/10 70% of the object will be under water

You Try: 80% 90% 60% 10% 30% 20% A. 0.3 g/cm3 D. 0.2 g/cm3 B. 0.8 g/cm3 E. 0.9 g/cm3 C. 0.6 g/cm3 F. 0.1 g/cm3 80% 90% 60% 10%

Draw a picture of a cube floating in water that has a density of 0 Draw a picture of a cube floating in water that has a density of 0.1 g/cm3

Match each density with its appropriate block letter 1.2 g/cm3 0.5 g/cm3 0.7 g/cm3 0.6 g/cm3 0.3 g/cm3 C D A

Observe the following diagrams: C 0.2g/cm3 4a. Based on the diagram, estimate the density of object A ____________ 0.4g/cm3 4c. Based on the diagram, estimate the density of object C ____________ 0.2g/cm3 4d. If block A was cut in half, what would its density be? _____________ Density does not change! 5. If 70% of the block was above water, what percent would be below the water line? ____________ 30 %

Density Identities – pg 37 Substance Density (g/mL) Air (g) 0.0013 Ice (s) 0.92 Alcohol (l) 0.8 Iron (s) 7.9 Aluminum(s) 2.7 Lead (s) 11.3 Cork (s) 0.2 Marble (s) Corn Syrup (l) 1.38 Mercury (l) 13.7 Diamond (s) 3.5 Rubber (s) 1.34 Gasoline (l) 0.7 Silver (s) 10.5 Glycerine (l) 1.26 Steel (s) 7.8 Gold (s) 19.3 Water (l) 1.00 14

Alcohol (density = 0.8 g/mL) I am a liquid. If you mix me with water, I float on top, but if you mix me with gasoline, I sink. What am I? Although I am a solid, I am so light that I can float in any liquid listed on the table. Who am I? In a mixture with water and corn syrup, I will always be in the middle. Who am I? I am a solid, I float in water, but not in alcohol. Who am I? Alcohol (density = 0.8 g/mL) Cork (density = 0.2 g/cm3) Glycerine (density = 1.26 g/mL) or Rubber (density = 1.34 g/mL) Ice (density = 0.92 g/cm3) 15

My density is unity (1.00g/mL.) Who am I? An object made of me is light enough to float in corn syrup, but not in water. Who am I? My density is unity (1.00g/mL.) Who am I? 7. Although we are not related, 1,000 grams of me will have the same volume as 1,000 grams of aluminum. Who am I? Rubber (density = 1.34 g/cm3) Water (density = 1.0 g/mL) Marble (density = 2.7 g/cm3) 16

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