Chapter 6 Molecules And Matter

Question 1

6.1 What is the equation for density?

Answer 1

Density = Mass/Volume

Question 2

6.1 How to measure the density of a solid object?

Answer 2

1. To measure the mass, make sure the balance is zero.
2. To measure the volume use rulers of a regular shape.
   If the shape is irregular, lower it on a thread into a measuring cylinder partly filled with water. Work out the volume of the object by the rise in the water level.

Question 3

6.1 How to measure the density of a liquid

Answer 3

1. For the volume, use a measuring cylinder to find the volume of a particular liquid
2. For the mass use a balance and measure the mass of the container.
   Next, pour the liquid to measure the mass of the total mass of the beaker and the liquid.
   After, subtract the mass of the empty beaker from the total mass of the beaker and the liquid

Question 4

6.1 What happens when objects have a lower density of water?

Answer 4

They float in water

Question 5

6.2 What is a solid state of matter like?

Answer 5

The particles of a SOLID are held next to each other in fixed positions. They are the least energetic of states of matter. Fixed shape and fixed volume

Question 6

6.2 What is a liquid state of matter like?

Answer 6

The particles of a liquid move about at random and are in contact with each other. They are more energetic than particles in a solid. No fixed shape but a fixed volume

Question 7

6.2 Gas state of matter

Answer 7

Particle of a gas move about randomly and are far apart (less dense than solids and liquids). They are the most energetic of the states of matter.

Question 8

6.2 Process of a solid - liquid - gas

Answer 8

Melting and boiling

Question 9

6.2 Process of a gas - liquid - solid

Answer 9

Condensation to freezing

Question 10

6.2 Solid to gas process

Answer 10

Sublimation

Question 11

6.3 What is needed to melt a solid or boil a liquid?

Answer 11

Energy

Question 12

6.3 What is the difference between boiling and evaporation?

Answer 12

Boiling occurs throughout a liquid at its boiling point.

Evaporation occurs from the surface of a liquid when its temperature is below its melting point.

Question 13

6.3 What does the flat section of a temperature-time graph?

Answer 13

It gives the melting point or the boiling point of a substance.

Question 14

6.4 How do you increase the internal energy of a substance?

Answer 14

You increase the temperature

Question 15

6.4 How can you explain if a substance is solid, liquid or gas?

Answer 15

The strength of the forces of attraction between the particles of a substance.

Question 16

6.4 When a substance is heated and its temperature rises, what happens to its kinetic energy?

Answer 16

The kinetic energy increases

Question 17

6.4 When a substance is heated, if it melts or boils, what happens to the potential energy?

Answer 17

The potential energy of its particles increases

Question 18

6.4 What causes pressure on a surface?

Answer 18

It is caused by the particles of the gas repeatedly heating the surface.

Question 19

6.5 What is the latent heat?

Answer 19

Latent heat is the energy needed for a substance to change its state without changing its temperature.

Question 20

6.5 What is the specific latent heat of fusion?

Answer 20

The energy needed to melt 1kg of a substance without changing its temperature.

Question 21

6.5 Specific latent heat equation

Answer 21

Energy/mass

Question 22

6.5 How do you measure the specific latent heat of ice measured?

Answer 22

It can be measured using a low-voltage heater to melt the ice

Question 23

6.2 What happens to the mass of a substance when it changes its state

Answer 23

The mass of the substance is conserved meaning it stays he same. This is because the number of particles are the same

Question 24

Explain the movement of particles in a solid

Answer 24

• The particles of soild are held in fixed positions
• They vibrate about their fixed positions
• Solid keeps its own shape
• Least energy

Question 25

Explain the particles of a liquid

Answer 25

• They are in contact with each other.
• They move about randomly
• Liquid doesn’t have its own shape, and it can flow
• Medium energy

Question 26

Explain the particles of gas

Answer 26

• They move randomly and faster than liquid
• They are much further apart from each other than the particles of a liquid
• Density of gas is much less than that of a solid and liquid