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.
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
takes up
= how much space an object
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. 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. 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.
It occupies a volume of 80 mL.
What is the mass?
D
= 10 g/mL
M
=?
V
= 80 mL
M=DxV
= 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 1.025 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.
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?
D
=?
M
= 23 grams
V
= 10 mL
D = 2.3 g/mL
14. What is the density of
object A?
D
=?
M
=5g
V
= 5 cm3
= 5g / 5 cm3
D = 1 g/cm3
FLOAT
15. What is the density of
object B?
D
=?
M
= 10 g
V
= 14 cm3
= 10g / 14 cm3
D = 0.7 g/cm3
FLOAT
16. What is the density of
object B?
D
=?
M
= 23 g
V
= 24 cm3
= 23g / 24 cm3
D = 0.958 g/cm3
FLOAT
17. An object with a mass of
24g and a volume of 32 mL is
most like what substance?
D
=?
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=DxV
= 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 = 3.977 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