Topic 6 - Molecules and Matter

Question 1

What is the formula of Density

Answer 1

Density (p) = Mass (m) / Volume (m[cubed])

Question 2

A wooden post has a volume of 0.025 m (cubed) and a mass of 20kg. Calculate its density in kg/m(3)

Answer 2

800 kg/m(3)

Question 3

How can you convert from kg/m(3) to g/cm(3)

Answer 3

divide by 1000

Question 4

Calculate the volume of 420 kg of Aluminium that has a density of 2710 kg/m (3)

Answer 4

0.155 m (3)

Question 5

How do you find the volume of a regular shape?

Answer 5

Length x Width x Height

Question 6

How do you find the volume of a irregular shape?

Answer 6

You have to use a Eureka can and a measuring cylinder. When you place a solid into the Eureka can, the volume of water is exactly equal to the solid.

Question 7

How do you find the density of a liquid?

Answer 7

Put a beaker on a balance. Pour the liquid into the beaker like 10 ml (which is the same thing as 10cm(3) ) and record the mass . Divide the mass by the volume. (Remember to 0 the balance after putting on the beaker)

Question 8

A measuring cylinder contained a volume of 120cm cubed of a particular liquid. The liquid was poured into an empty beaker of mass (51 grams). The total mass of the beaker and the liquid was 145g. Find the density of this liquid.

Answer 8

780kg/m(3)

Mass of liquid = 145 - 51 = 94g

density = mass/volume = 94g/120cm(cubed) = 0.094 kg / 0.000120 m (3) = 780kg/m (3)

Question 9

What is it called when gas is cooled to a liquid?

Answer 9

Condensation

Question 10

What is it called when liquid is heated to a gas?

Answer 10

Boiling

Question 11

What is it called when is a solid is heated to a gas?

Answer 11

Sublimation

Question 12

What is it called when a gas is cooled to a solid?

Answer 12

Deposition

Question 13

What happens to the particles of a substance when the temperature is increased?

Answer 13

Particles move faster.

Question 14

Describe the particles in a solid state:

Answer 14

The Particles are held next to each other in fixed positions. They vibrate in their fixed positions, so the solid keeps its own shape. (strong force of attraction)

Question 15

Describe the particles in a liquid state:

Answer 15

The particles are in contact with each other. They move about at random. It doesn’t have its own shape and can flow.

(Breaks free of their bond once heated from solid because it vibrates more since it has more energy)

Question 16

Describe the particles in a gas state:

Answer 16

Particles move about at random much faster than they do in a liquid. They are much further apart from each other than liquid, and therefore the density of a gas is much less of that of a solid or liquid.

(Forces of attraction very weak. Bonds are completely broken and they gain more energy)

Question 17

What happens when you cool a gas down?

Answer 17

The particles won’t have enough energy to overcome the forces of attraction, so bonds will start to form, condensing it.