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Name ______________________ Class __________________ Date _______________Physical Science Units and Measurement
Density practice problems #1 – Answer Key
For full credit: Show your work and place a box around your final answer – be sure to include units
1. A block of wood has a mass of 500 g and a volume of 750 cm3. What is the density of the wood in g/cm3?
2. A piece of lead has a mass of 0.5 kg and a volume of 76.2 cm3. What is the density of lead in g/cm3?
3. What is the volume of 4.5 kg of butter? (density = 0.86 g/cm3)
To solve this problem, you need to follow the 5-step problem solving method:
Step 1: Identify all of the knowns in the problem
Knowns:
€
m = 500g
V = 750cm3
Step 2: Identify all of the unknowns in the problemUnknowns:
€
ρ =?
Step 3: Decide on an equation needed to solve the problem. Write it .
Equation:
€
ρ =m
V
Step 4: Substitute all numbers with units into equation.
€
ρ =mV
ρ =500g
750cm3
Step 4: Solve the equation. Don’t forget units on all numbers!
€
ρ =0.67g
cm3
To solve this problem, you need to follow the 5-step problem solving method. This one looks like this.
€
m = 0.5kg
m = 500g
V = 76.2cm3
ρ = ?
€
ρ =mV
ρ =500g
76.2cm3
ρ = 6.56g
cm3
Note: Mass had to be converted to g from kg first.Also, all the equal signs are lined up vertically.
Name ______________________ Class __________________ Date _______________Physical Science Units and Measurement
4. What is the mass of 1500 cm3 of ice? (density = 0.92 g/cm3)
5. What is the mass of a block of pine with the following dimensions: 5 cm x 5 cm x 10 cm (density = 0.710 g/cm3)
€
m = 4.5kg
m = 4500g
ρ = 0.86g
cm3
V = ?
€
ρ =m
V
V =m
ρ
V =4500g
0.86g
cm3
V = 5232cm3
Note: We had to solve for volume, so we solved the equation for V first.
€
V =1500cm3
ρ = 0.92g
cm3
m = ?
€
ρ =m
Vm = ρ ⋅V
m = 0.92g
cm3⋅1500cm3
m =1380g
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l = 5cm
w = 5cm
h =10cm
V = ?
V = l ⋅w ⋅h
V = 5cm ⋅5cm ⋅10cm
V = 250cm3
€
V = 250cm3
ρ = 0.710g
cm3
m = ?
€
ρ =m
Vm = ρ ⋅V
m = 0.710g
cm3⋅250cm3
m =177.5g
Note: We had to solve for volume, so we solved the equation for V first.