P6

Question 1

The equation for density (rho) is

Answer 1

Mass (m) (kg) / volume (v) (m3)

Question 2

What does the density of an object depend on?

Answer 2

What its made of and how its particles are arranged

Question 3

If you compress an object, what will happen to the arrangment of the particles?

Answer 3

The particles woukd move closer together, and it would become more dense but you wouldn’t be decreasing its volume.

Question 4

Describe the characteristics of a liquid

Answer 4

LIQUID: there is weaker forces of attraction between particles. The particles are flose together, but can move past each other in irregular arrangments. They have more energy than the particles in a solid - move in random directions at low speeds. Generally less dense than solids

Question 5

Desribe the characteristics of solids

Answer 5

Strong forces of attraction hold the particles close together in a fixed, regular arrangement.
The particles don’t habe much energy so they can only vibrate about their fixed positions. The density is generally highest in this state as the particles are closest together.

Question 6

Liquid to solid is

Answer 6

Freezing

Question 7

Solid to liquid is

Answer 7

Melting

Question 8

Liquid to gas is

Answer 8

Evaporation

Question 9

Gas to liquid

Answer 9

Condensation

Question 10

Gas to solid

Answer 10

Desublimation

Question 11

Solid to gas

Answer 11

Sublimation

Question 12

The boiling and melting point of a substance refers to

Answer 12

The temperature at which is will change state (melting point being solid to liquid and boiling point being liquid to gas

Question 13

The energy transferred to a substance when it changes state is called

Answer 13

Latent heat

Question 14

The temperature of the substance does or does not change at the point where it changes state?

Answer 14

Does not

Question 15

What is the internal energy of a substance

Answer 15

Is the combined energy of the kinetic and potential energy of the particles in the substance (or system)

Question 16

What is potential energy

Answer 16

The potential energy The particles have due to their position. Bigger the distance between particles the greater potential energy they have.

Question 17

What happens if a gas is given more energy?

Answer 17

When a gas is heated (provided with more energy) its molecules gain more kinetic energy and move faster. The molecules therefore collide with surfsces more frequently and with more force.

Question 18

What is temperature

Answer 18

Temperature is a measure of how hot or cold something is

Question 19

Increasing the temperature of any sealed gas container

Answer 19

Increases the pressure

Question 20

Increasing the temp of any sealed gas container increases the pressure. Give two reasons why?

Answer 20

The average kinetic energy of the molecules increases as heat energy is transferred to
them.
• The average speed of the molecules increases as the kinetic energy increases.
This causes the molecules to hit the sides of the container more frequently and with more force, therefore greater pressure.

Question 21

Equation for energy and latent heat and mass

Answer 21

Energy = mass x specific latent heat

Question 22

Pressure x volume =

Answer 22

Constant

Question 23

P1xv2

Answer 23

P2xv2

Question 24

The bottle is filled with water and inside is a small packet of sauce which also has some air sealed in the packet. As the bottle is squeezed the sauce packet sinks. Why?

Answer 24

When you squeeze the bottle inward, you are reducing the volume of the bottle. This reduction in volume increases the pressure of all of the gas, including air in the sauce packet. The increased pressure of the air and therefore decreased volume will make it slightly more dense reducing its ‘buoyancy’ causing it to sink lower.

Question 25

Describe the characteristics of gases

Answer 25

There are almost no forces of attraction between particles. The particles have more energy than in liquids and solids so are free to move in random directions. Have low densities

Question 26

If the temperature changes, it depends on

Answer 26

The mass of the substance, what it’s made of and the energy input

Question 27

Energy (E), mass (M) and specific latent heat (L)

Answer 27

Energy (J) = mass (kg) x specific latent heay (J/KG)

Question 28

When a substance is melting or boiling, you’re still putting in energy and so

Answer 28

Increasing the internal energy, but the energy is used for breaking bonds between particles rather than raising the temperature

Question 29

When a substance is condensing or freezing, bonds are _________ beterrn particles, which releases energy. This means?

Answer 29

FORMING. The internal energy decreases, but the temperature doesn’t go down until all the substance has turned to liquid or solid.

Question 30

What is specific latent heat of a substance

Answer 30

The amount of energy needed to change 1kg of it from one state to another without changing its temperature