11.1 Density

Question 1

What is the density of a substance

Answer 1

Mass per unit volume

Question 2

Density ρ equation

Answer 2

ρ = m/v

Question 3

What is the unit of density

Answer 3

kg m^-3

Question 4

Find the density of a solid

Answer 4

Measure its mass using a top pan balance
Measure its dimensions using vernier calipers or a micrometer and calculate its volume using the appropriate equation
Calculate density from mass/volume

Question 5

Find the density of a liquid

Answer 5

Measure the mass of an empty measuring cylinder
Pour some of the liquid into the measuring cylinder and measure the volume of the liquid directly
Use as much liquid as possible to reduce the percentage error in your measurement
Measure the mass of the cylinder and liquid to enable the mass of the liquid to be calculated
Calculate the density from mass/volume

Question 6

Find the density of an irregular solid

Answer 6

Measure the mass of the object
Immerse the object on a thread in liquid in a measuring cylinder, observe the increase in the liquid level, this is the volume of the object
Calculate the density of the object from its mass/volume

Question 7

What is an alloy

Answer 7

A solid mixture of two or more metals

Question 8

Mass of an alloy equation

Answer 8

m=ρAVA +ρBVB

Note: the A and B are subscripts

Question 9

Density of alloy equation

Answer 9

ρ = m/V = ρAVA + ρBVB / V = ρAVA /V + ρBVB /V

Question 10

Density of air

Answer 10

1.2 kgm^-3

Question 11

Density of aluminium

Answer 11

2700 kgm^-3

Question 12

Density of copper

Answer 12

8900 kgm^-3

Question 13

Density of gold

Answer 13

19300 kgm^-3

Question 14

Density of oxygen

Answer 14

1.3 kgm^-3

Question 15

Density of water

Answer 15

1000 kgm^-3