Density

Introduction

Introduction

•We can see the difference in density of different materials when we look at ...

•wood floating on water

•helium balloons floating in the air

Introduction

•We can see the difference in density of different materials when we look at ...

•iron sinking in water

•lava lamps

Introduction

Properties

Properties

•Density is an intensive property of matter.

•The density of matter does not depend on the amount of matter.

•Density does depend on the composition of the matter

Properties

•Density is the mass of the matter divided by the volume of the matter.

•The density of matter generally decreases as the temperature of the matter increases.

D =mV

Properties

•The density of some materials is given in this chart:

MaterialMaterial D (g/mL)D (g/mL) MaterialMaterial D (g/L)D (g/L)

gold 19.3carbon dioxide

1.83

mercury 13.6 argon 1.66lead 11.4 air 1.20

copper 8.86 helium 0.166corn oil 0.922 hydrogen 0.084water 1.000 methane 0.665

Properties

Doing the Math

Doing the Math•Density is the mass of the matter divided

by the volume of the matter.

•The volume of matter is the mass divided by the density.

•The mass of matter is the density times the volume.

D =mV

V =mD

m = D•V

Doing the Math

Examples

ExamplesExample 1:

ExamplesExample 1:

A block of wood has a length of 15 cm, a width of 10. cm, and a height of 5.0 cm. The block also has a mass of 340 g. What is the density of the block?

ExamplesExample 1:

A block of wood has a length of 15 cm, a width of 10. cm, and a height of 5.0 cm. The block also has a mass of 340 g. What is the density of the block?V = l•w•h = (15 cm)(10. cm)(5.0 cm)

ExamplesExample 1:

A block of wood has a length of 15 cm, a width of 10. cm, and a height of 5.0 cm. The block also has a mass of 340 g. What is the density of the block?V = l•w•h = (15 cm)(10. cm)(5.0 cm) = 750 cm3

ExamplesExample 1:

A block of wood has a length of 15 cm, a width of 10. cm, and a height of 5.0 cm. The block also has a mass of 340 g. What is the density of the block?

D = m V

V = l•w•h = (15 cm)(10. cm)(5.0 cm) = 750 cm3

ExamplesExample 1:

A block of wood has a length of 15 cm, a width of 10. cm, and a height of 5.0 cm. The block also has a mass of 340 g. What is the density of the block?

D = = m 340 gV 750 cm3

V = l•w•h = (15 cm)(10. cm)(5.0 cm) = 750 cm3

ExamplesExample 1:

A block of wood has a length of 15 cm, a width of 10. cm, and a height of 5.0 cm. The block also has a mass of 340 g. What is the density of the block?

D = = = 0.453333333 g/cm3 m 340 gV 750 cm3

V = l•w•h = (15 cm)(10. cm)(5.0 cm) = 750 cm3

ExamplesExample 1:

A block of wood has a length of 15 cm, a width of 10. cm, and a height of 5.0 cm. The block also has a mass of 340 g. What is the density of the block?

D = = = 0.453333333 g/cm3 = 0.45 g/cm3

m 340 gV 750 cm3

V = l•w•h = (15 cm)(10. cm)(5.0 cm) = 750 cm3

ExamplesExample 1:

A block of wood has a length of 15 cm, a width of 10. cm, and a height of 5.0 cm. The block also has a mass of 340 g. What is the density of the block?

D = = = 0.453333333 g/cm3 = 0.45 g/cm3

m 340 gV 750 cm3

V = l•w•h = (15 cm)(10. cm)(5.0 cm) = 750 cm3

Examples

ExamplesExample 2:

ExamplesExample 2:

A block of lead has a mass of 37.4 g. Lead has a density of 11.4 g/cm3. What is the volume of the block?

Example 2:

A block of lead has a mass of 37.4 g. Lead has a density of 11.4 g/cm3. What is the volume of the block?

Examples

D = m V

Example 2:

A block of lead has a mass of 37.4 g. Lead has a density of 11.4 g/cm3. What is the volume of the block?

Examples

D = ➔ V = m m V D

Example 2:

A block of lead has a mass of 37.4 g. Lead has a density of 11.4 g/cm3. What is the volume of the block?

Examples

D = ➔ V = = m m 37.4 gV D 11.4 g/cm3

Example 2:

A block of lead has a mass of 37.4 g. Lead has a density of 11.4 g/cm3. What is the volume of the block?

Examples

D = ➔ V = = = 3.280701754 cm3

m m 37.4 gV D 11.4 g/cm3

Example 2:

A block of lead has a mass of 37.4 g. Lead has a density of 11.4 g/cm3. What is the volume of the block?

Examples

D = ➔ V = = = 3.280701754 cm3

m m 37.4 gV D 11.4 g/cm3

V = 3.28 cm3

Example 2:

A block of lead has a mass of 37.4 g. Lead has a density of 11.4 g/cm3. What is the volume of the block?

V = 3.28 cm3

Examples

D = ➔ V = = = 3.280701754 cm3

m m 37.4 gV D 11.4 g/cm3

Examples

ExamplesExample 3:

ExamplesExample 3:

What is the mass of a 20.0 cm length of copper wire with a density of 8.86 g/cm3 and a radius of 0.0500 cm? The volume of a cylinder is V = π•r2•l

ExamplesExample 3:

What is the mass of a 20.0 cm length of copper wire with a density of 8.86 g/cm3 and a radius of 0.0500 cm? The volume of a cylinder is V = π•r2•lV = π•r2•l

ExamplesExample 3:

What is the mass of a 20.0 cm length of copper wire with a density of 8.86 g/cm3 and a radius of 0.0500 cm? The volume of a cylinder is V = π•r2•lV = π•r2•l = π(0.05000 cm)2(20.0 cm)

ExamplesExample 3:

What is the mass of a 20.0 cm length of copper wire with a density of 8.86 g/cm3 and a radius of 0.0500 cm? The volume of a cylinder is V = π•r2•lV = π•r2•l = π(0.05000 cm)2(20.0 cm) = 0.157 cm3

ExamplesExample 3:

What is the mass of a 20.0 cm length of copper wire with a density of 8.86 g/cm3 and a radius of 0.0500 cm? The volume of a cylinder is V = π•r2•lV = π•r2•l = π(0.05000 cm)2(20.0 cm) = 0.157 cm3

D = m V

ExamplesExample 3:

What is the mass of a 20.0 cm length of copper wire with a density of 8.86 g/cm3 and a radius of 0.0500 cm? The volume of a cylinder is V = π•r2•lV = π•r2•l = π(0.05000 cm)2(20.0 cm) = 0.157 cm3

D = ➔ m V

ExamplesExample 3:

What is the mass of a 20.0 cm length of copper wire with a density of 8.86 g/cm3 and a radius of 0.0500 cm? The volume of a cylinder is V = π•r2•lV = π•r2•l = π(0.05000 cm)2(20.0 cm) = 0.157 cm3

D = ➔ m = D•V

m V

ExamplesExample 3:

What is the mass of a 20.0 cm length of copper wire with a density of 8.86 g/cm3 and a radius of 0.0500 cm? The volume of a cylinder is V = π•r2•lV = π•r2•l = π(0.05000 cm)2(20.0 cm) = 0.157 cm3

D = ➔ m = D•V = (8.86 g/cm3)(0.157 cm3)

m V

ExamplesExample 3:

What is the mass of a 20.0 cm length of copper wire with a density of 8.86 g/cm3 and a radius of 0.0500 cm? The volume of a cylinder is V = π•r2•lV = π•r2•l = π(0.05000 cm)2(20.0 cm) = 0.157 cm3

D = ➔ m = D•V = (8.86 g/cm3)(0.157 cm3)

m V m = 1.39 g

ExamplesExample 3:

What is the mass of a 20.0 cm length of copper wire with a density of 8.86 g/cm3 and a radius of 0.0500 cm? The volume of a cylinder is V = π•r2•lV = π•r2•l = π(0.0500 cm)2(20.0 cm) = 0.157 cm3

D = ➔ m = D•V = (8.86 g/cm3)(0.157 cm3)

m V m = 1.39 g