Density Practice Problems 1.key

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? 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 = 750cm 3

Step 2: Identify all of the unknowns in the problem Unknowns: 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. m V 500g r = 750cm 3

ρ=

Step 4: Solve the equation. Don’t forget units on all numbers! ρ = 0.67

g cm 3

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? To solve this problem, you need to follow the 5-step problem solving method. This one looks like this.

m Note: Mass had to be V converted to g from kg first. 500g r = 3 Also, all the = equal 3 3. VWhat is3 the volume of 4.5 kg of butter? (density 0.86signs g/cmare ) = 76.2cm 76.2cm lined up vertically. g r =? r = 6.56 3 cm m = 0.5kg m = 500g

ρ=

Name ______________________ Class __________________ Date _______________ Physical Science Units and Measurement

m = 4.5kg m = 4500g g r = 0.86 3 cm V =?

m V m V= r 4500g V= g 0.86 3 cm V = 5232cm 3

ρ=

Note: We had to solve for volume, so we solved the equation for V first.

4. What is the mass of 1500 cm3 of ice? (density = 0.92 g/cm3) V = 1500cm g r = 0.92 3 cm m=?

3

m V m = r ×V

ρ=

g ×1500cm 3 3 cm m = 1380g m = 0.92

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) l = 5cm w = 5cm h = 10cm V =? V = l ×w ×h V = 5cm ×5cm ×10cm V = 250cm 3

V = 250cm r = 0.710 m=?

3

g cm 3

m V m = r ×V

ρ=

g ×250cm 3 cm 3 m = 177.5g m = 0.710

Note: We had to solve for volume, so we solved the equation for V first.