Science exam answers Lesson 5

A student measures the mass of an 8 cm³ block of

brown sugar to be 12.9 g. What is the density of the

brown sugar? (1.6 g/cm³ )

D=m/V

=12.9/8

=1.6 g/cm³

A chef fills a 50 mL container with 43.5 g of cooking oil.

What is the density of the oil? (0.87 g/mL)

D=m/V

=43.5/50

=0.87 g/mL

Calculate the mass of a liquid with a density of 2.5 g/mL

and a volume of 15 mL. (37.5 g)

m=DxV

=2.5x15

m= 37.5g

Calculate the volume of a liquid with a density of 5.45

g/mL and a mass of 65 g. (11.93 mL)

V=m/D

= 65/5.45

V= 11.93 mL

A machine shop worker records the mass of an aluminum

cube as 176 g. If one side of the cube measures 4 cm,

what is the density of the aluminum? (2.75 g/cm3)

D=m/V

=176/64

= 2.75 g/cm³

V=LxWxh

=4x4x4

=64 cm³

A teacher performing a demonstration finds that a piece

of cork displaces 23.5 mL of water. The piece of cork has

a mass of 5.7 g. What is the density of the cork? (0.24

g/mL)

D=m/V

= 5.7/23.5

=0.24 g/mL

A piece of PVC plumbing pipe displaces 60 mL when

placed into a container of water. If the pipe has a mass of

78 g, what is the density of PVC? (1.3 g/mL)

D=m/V

= 78/60

=1.3 g/mL

A solid magnesium flare has a mass of 1300 g and a

volume of 743 cm³ . What is the density of the

magnesium? (1.75 g/cm³ )

D= m/V

= 1300/743

=1.75 g/cm³

A graduated cylinder has a mass of 50 g when empty.

When 30 mL of water is added, the graduated cylinder has

a mass of 80 g. If a rock is added to the graduated

cylinder, the water level rises to 75 mL and the total mass

is now 250 g. What is the density of the rock?

(Mass of Rock = 250 g–80(from cylinder and water) m =

170 g

Volume of Rock = 75 mL–30 mL(already there) = 45 mL

D=m/V

=170/45

=3.78 g/mL

A student performs an experiment with three unknown

fluids and obtains the following measurements:

Fluid A: m = 2060 g, V = 2000 mL (D = 1.03 g/mL)

Fluid B: m = 672 g, V = 850 mL (D = 0.79 g/mL)

Fluid C: m = 990 g, V = 1100 mL (D = 0.9 g/mL)

Draw how the fluids are layered if they were combined in

a beaker.

Bottom to Top: A, C, B)

Top to Bottom: B, C,A

Use your density skills to find the identity of the following

mystery objects.

Marble = 2.56g/cm³

Quartz = 2.64g/cm³

Diamond = 3.52g/cm³

Copper = 8.92g/cm³

Gold = 19.32g/cm³

Platinum = 21.4g/cm³

a) While digging in the backyard, you find an old coin. Its

mass is 26.76 g and its volume is 3 cm³ . What is the coin

made of?

b) You think you have found a diamond. Its mass is 5.28 g

and its volume is 2 cm³. What did you find?

c) You find a ring with a mass of 107 g. You fill a graduated

cylinder up with 10 mL of water and put the ring into the

cylinder. The water rises up to the 15 mL mark. What is

the ring made of?

d) There is a block on your desk that acts as a

paperweight. Its measurements are 3 cm by 4 cm by 6

cm. The block has a mass of 184.32 g. What is the block

made of?

a) (D = 8.92 g/cm³, copper)

D = m/V

= 26.76/3

= 8.92 g/cm³

b) (2.64 g/cm³,

quartz)

D = m/V

= 5.28/2

= 2.64 g/cm³

c) (D = 21.4 g/mL, platinum)

Volume = 15-10 = 5 mL

D = m/V

= 107/5

= 21.4 g/mL

d) (D = 2.56 g/cm³, marble)

Volume = LxWxH

= 3x4x6

= 72cm³

D = m/V

= 184.32/72

= 2.56 g/cm³