Chapter 5.8
Density
Mrs. Baldessari
Chemistry
Objective: You will define and calculate
density with appropriate units.
1
Density

2
Take a look at the two boxes below. Each box
has the same volume. If each ball has the
same mass, which box would weigh more?
Why?
Density
3

Answer: The box that has more balls has more
mass per unit of volume.

This property of matter is called density. The
density of a material helps to distinguish it
from other materials.

Density
d = mass/volume (g/ml)
Density

Calculate the density of each block.
Block I
Mass = 79.43 grams
Volume=29.8 ml
4
Block II
Mass = 25.41 grams
Volume = 29.8 ml
Density

Block I
–

Block II
–
5
Density = 79.43 grams / 29.8 ml
= 2.67 g/ml
Density = 25.41 grams / 29.8 ml
= 0.853 g/ml
Density units
Density compares the mass of an object to
its volume
D =
mass
= g
volume
mL
Note: 1 mL = 1 cm3
6
or
g
cm3
Density
7

Density is a physical characteristic of a
material and allows us to determine what each
block is made of.

All pieces of matter made of the same material
will have the same density.

Different matter will have different densities.
Example #1
A certain mineral has a mass of 17.8 g and a volume of
2.35 cm3. What is the density of this mineral?
mass
Density =
volume
17.8 g
Density =
2.35 cm3
3
Density = 7.57 g/cm
9
Example #2
•What is the mass of a 49.6 mL sample of a liquid, which
has a density of 0.85 g/mL?
mass
Density =
volume
x
0.85 g/mL =
49.6 mL
mass = x = 42 g
10
•Cover the variable that your are
solving for
•Perform the math operation as it is
shown in the triangle
m
D v
m=(D)(V)
Concept Check
Copper has a density of 8.96 g/cm3. If 75.0 g
of copper is added to 50.0 mL of water in a
graduated cylinder, to what volume reading
will the water level in the cylinder rise?
a)
b)
c)
d)
11
8.4 mL
41.6 mL
58.4 mL
83.7 mL
Having trouble with the math?
• Cover the variable
that your are solving
for
m
•Perform the math
operation as it is
shown in the triangle
d
12
v
Volume Displacement
A solid displaces a matching volume of water
when the solid is placed in water.
33 mL
25 mL
13
Learning Check
What is the density (g/cm3) of 48 g of a metal if the
metal raises the level of water in a graduated
cylinder from 25 mL to 33 mL?
1) 0.2 g/ cm3
2) 6 g/m3
3) 252 g/cm3
33 mL
25 mL
14
Solution
2) 6 g/cm3
Volume (mL) of water displaced
= 33 mL - 25 mL
= 8 mL
Volume of metal (cm3)
= 8 mL x 1 cm3 = 8 cm3
1 mL
Density of metal =
mass
= 48 g
= 6 g/cm3
15
volume
8 cm3
Learning Check
Which diagram represents the liquid layers in
the cylinder?
(K) Karo syrup (1.4 g/mL), (V) vegetable oil
(0.91 g/mL,) (W) water (1.0 g/mL)
1)
2)
3)
V
W
K
16
K
W
K
V
V
W
Solution
(K) Karo syrup (1.4 g/mL), (V) vegetable oil
(0.91 g/mL,) (W) water (1.0 g/mL)
1)
V
W
K
17
Density Connections
Mass
18
Volume
kg
L
g
mL (cm3)
mg
Learning Check
The density of octane, a component of
gasoline, is 0.702 g/mL. What is the mass, in
kg, of 875 mL of octane?
1) 0.614 kg
2) 614 kg
3) 1.25 kg
19
Solution
1) 0.614 kg
Unit plan: mL  g  kg
Equalities: 1 mL = 0.702 g
Setup:
20
875 mL x 0.702 g
x
1 mL
density
factor
and 1 kg = 1000 g
1 kg
= 0.614 kg
1000 g
metric
factor
Learning Check
If blood has a density of 1.05 g/mL, how
many liters of blood are donated if 575 g of
blood are given?
1) 0.548 L
2) 1.25 L
3) 1.83 L
21
Solution
1)
Unit Plan: g
575 g x
22
mL
L
1 mL x 1 L
=
1.05 g
1000 mL
0.548 L
Learning Check
A group of students collected 125 empty aluminum
cans to take to the recycling center. If 21 cans
make 1.0 pound of aluminum, how many liters of
aluminum (D=2.70 g/cm3) are obtained from the
cans? Note, 1 mL = 1 cm3
1) 1.0 L
23
2) 2.0 L
3) 4.0 L
Solution
1) 1.0 L
125 cans x 1.0 lb x 454 g x 1 cm3
21 cans 1 lb
2.70 g
x 1 mL x
1 cm3
24
1L
1000 mL
= 1.0 L
Learning Check
You have 3 metal samples. Which one will
displace the greatest volume of water?
1
2
3
25 g Al
2.70 g/mL
45 g of gold
19.3 g/mL
75 g of Lead
11.3 g/mL
25 Discuss your choice with another student.
Solution
1)
25 g Al x
1 mL =
2.70 g
25 g Al
2.70 g/mL
26
9.2 mL