P6 Molecules And Matter

Question 1

What is definition of melting point

Answer 1

Temperature at which a substances changes from a solid to a liquid

Question 2

What is definition of boiling point

Answer 2

Temperature at which a substance changes from a liquid to a gas

Question 3

What is internal energy

Answer 3

The sum of the kinetic and potential energy of the system

Question 4

What is specific latent heat

Answer 4

The amount of energy needed to change the state of 1kg of a substance

Question 5

What is difference between specific latent heat of fusion and vaporisation

Answer 5

Fusion is solid to liquid
Vaporisation is liquid to gas

Question 6

Wha is the unit of specific latent heat

Answer 6

J/Kg

Question 7

What is density

Answer 7

Measure of the ‘compactness’ of a substance. Relates the mass of a substance to how much space is takes up

Question 8

What is the formula for density

Answer 8

P=m/v
Density(kg/m3)= mass(kg)/volume(m3)

Question 9

How do you find the density of an irregular object

Answer 9

Fill eureka can with water and let water flow out from spout. Now the water is just below the spout so anything placed into the eueka can, can be measured with water displaced. Place an empty measuring cylinder below end of the spout. Place object in water and messure how much water displaced. Subsitute the objects mass in the density formula.

Question 10

What is internal energy

Answer 10

The total energy that its particles have in their kinetic and potential energy stores

Question 11

What is it called when a gas turns to a liquid

Answer 11

Condensing

Question 12

What is it called when a liquid turns to a solid

Answer 12

Freezing

Question 13

What is it called when a liquid turns to a gas

Answer 13

Boiling/evaporating

Question 14

What is it called when a solid turns to a liquid

Answer 14

Melting

Question 15

What is it called when a solid turns to a gas

Answer 15

Sublimating

Question 16

What is a change of state

Answer 16

Physical change of a substance meaning you dont end up with a new substance but its just the firm of the substance that changes

Question 17

What do the flat lines show in a heating graph

Answer 17

Shows energy is beung used to break bonds to change its state

Question 18

What is latent heat

Answer 18

Amount of energy needed to change the state of a substance

Question 19

What is specific latent heat

Answer 19

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

Question 20

What is specific latent heat of fusion

Answer 20

SLH for changing between a solid and a liquid

Question 21

What is SLH for vaporisation

Answer 21

SLH for changing between a liquid and a gas

Question 22

What is the equation to find out energy needed to change a state

Answer 22

E=mxL
Energy for a change in state (j) = mass(kg) x specific latent heat (j/kg)

Question 23

What is the relationship between volume and pressure

Answer 23

pV=constant
Pressure and volume = constant

Question 24

How can you increase pressure of a gas

Answer 24

Increase in temperature

Question 25

What does in increase in volume of gas do to its pressure

Answer 25

Decreases in pressure

Question 26

What is the equation for density and give units?

Answer 26

Density (Kg/m^3) = mass (Kg) / volume (m^3)

Question 27

How are the particles arranged in a dense material?

Answer 27

Closely packed together

Question 28

How do you find the density of a regular object?

Answer 28

Measure its mass using a weighing scale, measure the length, width, and height of the object to find its volume. Substitute the volume and mass into the density equation.

Question 29

How do you find the density of an irregular object?

Answer 29

Weigh the object with a weighing scale. Fill a Eureka can with water up to the spout. Place a measuring cylinder underneath the exit of the spout and place the object in the Eureka can. The volume of water displaced is the volume of the object.

Question 30

How do you find the density of a liquid?

Answer 30

Put a measuring cylinder on a weighing scale and tare it to 0. Pour 10ml of the liquid into the measuring cylinder and record the weight shown. Substitute the mass and volume in the density formula.

Question 31

What is the internal energy of a system?

Answer 31

The total energy that its particles have in their kinetic and potential energy store.

Question 32

What does heating a system do to the internal energy?

Answer 32

They gain energy in their kinetic energy which increases the internal energy.

Question 33

Explain the arrangement and energy of the particles in a solid.

Answer 33

Strong forces of attraction hold the particles together in a fixed and regular arrangement. The particles don't have much energy, so only vibrate about their fixed position.

Question 34

Explain the arrangement and energy of the particles in a liquid.

Answer 34

Moderate forces of attraction between particles. The particles are close together but can move past each other, forming irregular arrangements. They have more energy than particles in a solid.

Question 35

Explain the arrangement and energy of the particles in a gas.

Answer 35

Almost no forces of attraction between the particles. Particles have more energy than in liquids and solids. They are free to move and are moving in random directions at high speeds.

Question 36

What is pressure?

Answer 36

The force exerted per unit area.

Question 37

Explain how colliding gas particles create pressure.

Answer 37

Particles in gases are free to move around. As they move, they bang into each other and whatever else gets in the way. When they collide with something, they exert a force, and pressure is the amount of force exerted.

Question 38

How does increasing the temperature of a gas increase its pressure?

Answer 38

If you increase the temperature of the gas, you transfer energy to the kinetic energy stores of its particles. Therefore, the speed at which the particles vibrate increases, which will increase the force exerted.

Question 39

What does density measure?

Answer 39

The compactness of a substance.