Question

density test - 8th grade physical science
name: date: period:
part i - vocabulary
write the correct word from the word bank in each blank.
word bank: mass volume density g/cm³ g/ml water displacement

1. the amount of matter in an object is its.
2. the amount of space an object takes up is its.
3. the formula for density is divided by.
4. density is usually expressed in units of for solids and for liquids.
5. the method used to find the volume of an irregular solid is called.

part ii - multiple choice
circle the best answer.

1. if a cube of metal has a mass of 54 g and a volume of 9 cm³, its density is:

a) 6 g/cm³ b) 63 g/cm³ c) 0.17 g/cm³ d) 9 g/cm³

1. if an object has a density less than 1.0 g/ml, it will:

a) sink in water b) float in water c) dissolve in water d) stay suspended in water

1. which tool would you use to measure the mass of a rock?

a) graduated cylinder b) thermometer c) electronic scale d) ruler

1. which tool would you use to measure the volume of a liquid?

a) balance b) graduated cylinder c) ruler d) scale

1. a student measures the mass of a block as 24 g and the volume as 8 cm³. what is the blocks density?

a) 0.3 g/cm³ b) 3 g/cm³ c) 32 g/cm³ d) 4 g/cm³
part iii - show your work

1. a small rock has a mass of 45 g. when placed in a graduated cylinder, the water level rises from 25 ml to 40 ml.

a. what is the volume of the rock?
b. what is its density? (show work and include units.)

Explanation:

Part I - Vocabulary

1.

The amount of matter in an object is its mass.

2.

The amount of space an object takes up is its volume.

3.

The formula for density is mass divided by volume.

4.

Density is usually expressed in units of g/cm³ for solids and g/mL for liquids.

5.

The method used to find the volume of an irregular solid is called water displacement.

Part II - Multiple Choice

1.

Using the density formula \(
ho=\frac{m}{V} \), where \( m = 54\ g \) and \( V=9\ cm^{3} \), then \(
ho=\frac{54}{9}=6\ g/cm^{3} \). So the answer is a) \( 6\ g/cm^{3} \).

2.

If an object has a density less than \( 1.0\ g/mL \) (the density of water), it will float in water. So the answer is b) Float in water.

3.

An electronic scale is used to measure mass. A graduated cylinder measures volume, a thermometer measures temperature, and a ruler measures length. So the answer is c) Electronic Scale.

4.

A graduated cylinder is used to measure the volume of a liquid. A balance measures mass, a ruler measures length, and a scale usually measures mass. So the answer is b) Graduated cylinder.

5.

Using the density formula \(
ho=\frac{m}{V} \), where \( m = 24\ g \) and \( V = 8\ cm^{3} \), then \(
ho=\frac{24}{8}=3\ g/cm^{3} \). So the answer is b) \( 3\ g/cm^{3} \).

Part III - Show Your Work

a.

The volume of the rock is found by the water displacement method. \( V=V_{final}-V_{initial} \). Here, \( V_{final} = 40\ mL \) and \( V_{initial}=25\ mL \). So \( V = 40 - 25=15\ mL \) (since \( 1\ mL = 1\ cm^{3} \), the volume is also \( 15\ cm^{3} \)).

b.

Using the density formula \(
ho=\frac{m}{V} \), where \( m = 45\ g \) and \( V = 15\ cm^{3} \). Then \(
ho=\frac{45}{15}=3\ g/cm^{3} \).

Answer:

Part I - Vocabulary

1. mass
2. volume
3. mass; volume
4. \( g/cm^{3} \); \( g/mL \)
5. water displacement

Part II - Multiple Choice

1. a. \( 6\ g/cm^{3} \)
2. b. Float in water
3. c. Electronic Scale
4. b. Graduated cylinder
5. b. \( 3\ g/cm^{3} \)

Part III - Show Your Work

a. \( 15\ mL \) (or \( 15\ cm^{3} \))
b. \( 3\ g/cm^{3} \)