CP12a Particles and Density

Question 1

Density calculation

Answer 1

Density = mass/volume

Question 2

Density is measured in:

Answer 2

kilograms/metres cubed (kg/m3)

Question 3

Mass is measured in:

Answer 3

kilograms

Question 4

What factor affect the density of sea water?

Answer 4

Its temperature and saltiness

Question 5

Explain why liquids and gases can flow but solids cannot

Answer 5

In liquids, the forces of attraction between the particles are not strong enough to keep them in fixed position. In gases there are no forces of attraction. Particles in solids are held closely together by forces of attraction

Question 6

Explain why gases can be compressed but solids and liquids cannot

Answer 6

The particles in gases are far apart whereas the particles in both solids and liquids are very close together

Question 7

Arrangement of solids

Answer 7

Regular and close together

Question 8

Movement of solids

Answer 8

Particles vibrate in a fixed position

Question 9

Which state of matter can be compressed?

Answer 9

Gas

Question 10

Arrangement of liquids

Answer 10

Random and close together

Question 11

Movement of liquids

Answer 11

Move around eachother

Question 12

Arrangement of gases

Answer 12

Random and far apart

Question 13

Movement of gases

Answer 13

Fast in all directions

Question 14

Density

Answer 14

The mass of a certain volume of the substance

Question 15

Which state of matter is usually the most dense state?

Answer 15

Solid

Question 16

Which state of matter is usually the least dense?

Answer 16

Gas

Question 17

Which substance in solid form is less dense than its liquid form?

Answer 17

Ice (water)

Question 18

Explain how the arrangement of particles in a liquid explain its properties

Answer 18

Particles in a liquid are random and close together. This means they can move past eachother therefore liquids can flow and take the shape of their container. The fact the particles are close together means liquids cannot be compressed

Question 19

Explain why a substance becomes less dense when it changes from a liquid to a gas

Answer 19

It becomes less dense because the particles in a gas are spread out even further apart than in a liquid where the particles are close together

Question 20

CORE PRACTICAL: INVESTIGATING DENSITIES

Method to measure the densities of liquids

Answer 20

1) Put an empty beaker on a balance, and set the balance to zero
2) Use a measuring cylinder to measure 50cm3 of a liquid and then pour it into the beaker
3) Write down the reading on the balance. This is 50cm3 of the liquid

Question 21

CORE PRACTICAL: INVESTIGATING DENSITIES

Method to measure the densities of liquids

Answer 21

1) Find the mass of the solid
2) Stand a displacement can on the bench with its spout over a bowl and fill it with water
3) Hold a measuring cylinder under the spout and drop object in to the can (if it floats push it under water)
4) The water collected in measuring cylinder is the same as the volume of the object