1. Remember the Triangle M
D V

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

3. 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

4. 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

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

6. 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)

7. 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

8. 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

9. 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

10. 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

11. 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

12. 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

13. 12. Beaker
STYROFOAM
BALSA WOOD
ICE
WATER
BONE
GOLD

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

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

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

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

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

19. 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

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

21. 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

22. 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

23. Density Practice
20 points total
Record score on top page

24. 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

25. 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

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

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

28. 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

29. Indicators to find pH

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