chapter 5.8 density - beachwood high school 8 density.pdf · 2011-09-25 · cylinder from 25 ml to...
TRANSCRIPT
Chapter 5.8 Density Mrs. Baldessari
Chemistry
Objective: You will define and calculate
density with appropriate units.
1
Density
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?
2
Density
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)
3
Density
Calculate the density of each block.
Block I Block II
Mass = 79.43 grams Mass = 25.41 grams
Volume=29.8 ml Volume = 29.8 ml
4
Density
Block I
– Density = 79.43 grams / 29.8 ml
= 2.67 g/ml
Block II
– Density = 25.41 grams / 29.8 ml
= 0.853 g/ml
5
6
Density units
Density compares the mass of an object to
its volume
D = mass = g or g
volume mL cm3
Note: 1 mL = 1 cm3
Density
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.
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Example #1
massDensity =
volume
3
17.8 gDensity =
2.35 cm
Density =37.57 g/cm
A certain mineral has a mass of 17.8 g and a volume of
2.35 cm3. What is the density of this mineral?
9
Example #2
massDensity =
volume
0.85 g/mL = 49.6 mL
x
mass = = 42 gx
•What is the mass of a 49.6 mL sample of a liquid, which
has a density of 0.85 g/mL?
•Cover the variable that your are
solving for
•Perform the math operation as it is
shown in the triangle
m=(D)(V)
D v
m
10
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) 8.4 mL
b) 41.6 mL
c) 58.4 mL
d) 83.7 mL
11
Having trouble with the math?
m
d v
• Cover the variable
that your are solving
for
•Perform the math
operation as it is
shown in the triangle
12
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
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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
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)
K
K
W
W
W
V
V
V
K
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Solution
(K) Karo syrup (1.4 g/mL), (V) vegetable oil
(0.91 g/mL,) (W) water (1.0 g/mL)
1)
K
W
V
18
Density Connections
Mass 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
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Solution
1) 0.614 kg
Unit plan: mL g kg Equalities: 1 mL = 0.702 g and 1 kg = 1000 g Setup:
875 mL x 0.702 g x 1 kg = 0.614 kg
1 mL 1000 g
density metric
factor 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
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Solution
1)
Unit Plan: g mL L
575 g x 1 mL x 1 L = 0.548 L
1.05 g 1000 mL
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 2) 2.0 L 3) 4.0 L
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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 L = 1.0 L
1 cm3 1000 mL
25
Learning Check
You have 3 metal samples. Which one will
displace the greatest volume of water?
1 2 3
Discuss your choice with another student.
25 g Al
2.70 g/mL
45 g of gold
19.3 g/mL 75 g of Lead
11.3 g/mL
26
Solution
1) 25 g Al x 1 mL = 9.2 mL
2.70 g
25 g Al
2.70 g/mL