# Remember the Triangle M D V.

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Remember the Triangle M D V

1. State the formula for density in words and mathematical symbols
Density is mass divided by volume. D = M/V

2. A rock has a mass of 210 grams and occupies a volume of 70 cm3
2. A rock has a mass of 210 grams and occupies a volume of 70 cm3. What is its density? D = M/V = 210g/70 cm3 D = 3 g/cm3

3. An unknown liquid occupies a volume of 5 mL and has a mass of 40 grams. Find its density:
D = M/V = 40g / 5 mL D = 8 g/mL

4. Define the following words:
MASS = the amount of matter in a substance VOLUME = how much space an object takes up

5. How does the volume occupied by a cubic centimeter (cm3) compare with the volume occupied by a milliliter (mL) The volume is the same (cm3 is just measured for solids and mL is measured for liquids)

6. A rectangular solid of unknown density is 5 m long, 2 m high and 4 m wide. The mass of this solid is 300 grams. Calculate the density: D = ? M = 300 g V = 5 x 4 x 2 = 40 m3 = 300g / 40 m3 D = 7.5 g/m3

7. A rock occupies a volume of 20 cm3 and has a mass of 54 grams
7. A rock occupies a volume of 20 cm3 and has a mass of 54 grams. Find the density of the rock: D = ? M = 54 g V = 20 cm3 = 54g / 20 cm3 D = 2.7 g/cm3

8. A rock has a density of 4 g/mL and a mass of 16 grams
8. A rock has a density of 4 g/mL and a mass of 16 grams. What is the volume this rock occupies? D = 4 g/mL M = 16 g V = ? V = M/D = 16 g / 4 g/mL V = 4 mL

9. An unknown substance from planet X has a density of 10 g/mL
9. An unknown substance from planet X has a density of 10 g/mL. It occupies a volume of 80 mL. What is the mass? D = 10 g/mL M = ? V = 80 mL M = D x V = 10 g/mL x 80 mL M = 800 g

10. Water has a density of 1 g/mL and ocean water has a density of 1
10. Water has a density of 1 g/mL and ocean water has a density of g/mL. Why? Ocean water has salt in it and salt is more dense than water

11. A cube made of an unknown material has a height of 9 cm
11. A cube made of an unknown material has a height of 9 cm. The mass of this cube is 3,645 g. Calculate the density. D = ? M = 3645 g V = 9x9x9 = 729 cm3 = 3645g / 729 cm3 D = 5 g/cm3

12. Beaker STYROFOAM BALSA WOOD ICE WATER BONE GOLD

13. What is the volume of the rock?
V= 30 ml – 20 ml = 10 mL

13. What is the density of the rock?
M = 23 grams V = 10 mL D = 2.3 g/mL

14. What is the density of object A?
M = 5 g V = 5 cm3 = 5g / 5 cm3 D = 1 g/cm3 FLOAT

15. What is the density of object B?
M = 10 g V = 14 cm3 = 10g / 14 cm3 D = 0.7 g/cm3 FLOAT

16. What is the density of object B?
M = 23 g V = 24 cm3 = 23g / 24 cm3 D = g/cm3 FLOAT

17. An object with a mass of 24g and a volume of 32 mL is most like what substance?
M = 24 g V = 32 mL = 24g / 32 mL D = 0.75 g/mL WOOD

18. What is the only object in the table that would sink in corn syrup?
Copper

19. What is the mass of 100 mL of corn oil?
D = 0.92 g/cm3 M = ? V = 100 mL M = D x V = 0.92 g/cm3 x 100 mL M = 92 g

20. What is the volume of 35g of copper?
D = 8.80 g/cm3 M = 35g V = ? V = M/D = 35g / 8.80 g/cm3 V = cm3

Density Practice 20 points total Record score on top page

Density Table Contest With your table, create one density problem
Tables will have 2 minutes to answer the questions at each table Write final question & table number on whiteboard RULES: Must have numbers less that 1000 Must include units in question Must provide teacher with the correct answer

Learning Goal: Density
4 – I can find and compare the density of different substances 3 – I can compare the density of different substances 2 – I know the equation 1 – I need to review

TOPIC: pH EQ: What does pH tell us about different substances?

pH – a measurement of how acidic or basic a substance is (and the rxn with water)

Applications with pH Skin levels (more acidic) (lotions, soaps, creams, face wash…) Plant growth Calcium Deposits – lime away, use an acid Teeth – acids break down enamel  yellow teeth Pool Care

Indicators to find pH

pH Levels? A property to help us better understand a substance