P6

Question 1

Density of a substance is deined as …

Answer 1

Its mass per unit of volume

Question 2

Equation of density

Answer 2

Mass(kg)
Density(kg/m^3)=—————-
Volume(m^3)

Question 3

Ways to find the volume of a regular solid

Answer 3

Use a millimetre ruler
Vernier callipers
Micrometer

Question 4

How to find the volume of a small irregular solid

Answer 4

Lower it on a thread into a measuring cylinder partly filled with water. You can work out the volume from the rise in the water level.

Question 5

How to find the volume of a liquid

Answer 5

Use a measuring cylinder

Question 6

How to find the mass of a liquid

Answer 6

Subtract mass of emoty beaker by total mass of the beaker and liquid.

Question 7

Which states flow

Answer 7

Liquids and gases

Question 8

Which states have a fixed shape

Answer 8

S-Fixed
L-Fits container shape
G-Fills container

Question 9

Which states have a fixed volume

Answer 9

S-Fixed
L-Fixed
G-Can be changed

Question 10

States density comparisons

Answer 10

S-Much higher than a gas
L-Much higher than a gas
G-Lower than a solid or a liquid

Question 11

Changes of state are ….. changes

Answer 11

Physical

Question 12

Why are changes of state physical changes

Answer 12

Beacuse no new substances are produced and if a physical change is reversed, the substance recovers its original properties.

Question 13

When solid carbon dioxide (dry ice) warms up, the solid turns into … directly

Answer 13

gas

Question 14

Why is the mass of a substance conserved when it changes state

Answer 14

Because the number of particles is unchanged.

Question 15

When the temp of the substance is increased, the particles move…

Answer 15

Faster

Question 16

Arrangement of particles in a solid

Answer 16

Regular arrangement. The particles are held next to each other in fixed positions. They vibrate around their fixed postions.

Question 17

Arrangement of particles in a liquid

Answer 17

They are in contact with each other. They move about at random.

Question 18

Arrangement of particles in a gas

Answer 18

The particles move about at random more quickly. On avarege are much further apart.

Question 19

For a given amount of a substance, its particles have more energy on a gas state than in

Answer 19

Another state

Question 20

For any pure substance undergoing a change of state…

Answer 20

Its temperature stays the same while the cange of state is taking place.

Question 21

The melting point of a solid and the boiling point of a liquid are affected by…

Answer 21

Impurities on the substance

Question 22

The melting point of water is lowered if you add

Answer 22

Salt, which is why salt is added to the grit that’ used for gritting roads in freezing weather, meaning roads don’t get icy until they are colder.

Question 23

How to measure the melting point of a substance

Answer 23

Put a solid in a test tube in a beaker of water, heat until melts and record.

Question 24

The enegy transerred to a substance when it changes its state is called

Answer 24

Latent heat. It is ‘hidden’ by the substance because its temperature doesn’t chnage at the substances’ melting point or at its boiling point.

Question 25

Fusion is sometimes used to describe melting because

Answer 25

different solids can be joined or 'fused together when they melt

Question 26

Evaporation from a liquid happens at its surface when the liquid is below its boiling point. At its boiling point,....

Answer 26

a liquid boils because the bubbles of vapour form inside the liquid and rise to the surface to release the gas

Question 27

The energy stored by the particles of a substance is called the substance's..

Answer 27

Internal energy. This is the enrgy that is caused by their individual motion and positions.

Question 28

The internal energy of a the particles is the sum of:

Answer 28

The kinetic energy due to their individual motions relative to each other, and the potential energy due to their individual postions relative to each other. Conclusion: The internal energy of a substance is the total energy in the kinetic and potential energy stores of all the particles in the substance that is caused by their individual motions and positions.

Question 29

Internal energy does not include

Answer 29

Gravitational potential energy or the kinetic energy that is caused by the motion of the whole susbtance.

Question 30

Heating a substance changes the internal energy of the substance by...

Answer 30

increasing the energy of its particles. Because of this, the temp of the substance increases or its physical state changes .

Question 31

When the temp of a substance increases or decreases...

Answer 31

the total kinetic energy of its particles increases or decreases.

Question 32

When the physical state of a substance changes, ...

Answer 32

the total potential energy of its particles changes.

Question 33

In solids, particles are arranged in a .....

Answer 33

Three-dimensional structure

Question 34

When a solid is heated, ....

Answer 34

the particles' energy stores increase and they vibrate more. | If a solid is heated enough it melts because the particles have gained enough energy to break away from the structure.

Question 35

What are the forces of attraction between particles in liquids like?

Answer 35

Weaker than in solids. They are not strong enough to hold the particles together in a rigid structure. However, they are strong enough to stop them moving away from each other completely at the surface.

Question 36

What happens to the particles when a liquid is heated?

Answer 36

Some of the particles gain enough energy to break away from the other partcicles. The molecules that escape from the liquid in a gas state are above the liquid.

Question 37

Describe the forces of attraction and state charactersitics of gases.

Answer 37

The forces of attraction between the particles are so weak, they are insignificant. The particles move about at a high speed in random directions, colliding with each other and the internal surface of the conatiner. The pressure of a gas on a solid structure such as a conatiner is caused by the force of impacts of the gas particles with the surface.

Question 38

What happens to the particles in a gas when it is heated?

Answer 38

Its partciles gain kinetic energy and on avergae move faster. This causes the pressure pf the gas to increase because the particles collide with the container surface more often and with more force.

Question 39

When a solid substance is heated at its melting point, the substance melts and turns into a liquid. Its temp. stays constant until all of the substance has melted. The energy supplied is called ...................................?

Answer 39

Latent heat of fusion. It is the energy needed by the paricles to break free from each other.

Question 40

What is the specific latent heat of fusion of a substance?

Answer 40

The energy needed to change the state of 1kg of the substance from solid to liquid at its melting point (i.e.without changing the temperature).

Question 41

What is the unit of the specific latent heat of fusion?

Answer 41

Joule per kilogram (J/kg)

Question 42

Formula for specific latent heat of fusion

Answer 42

If energy E is transferred to a solid at its melting point, the mass m of the susbtamce melts without change in temeperature: energy E (joules) specific latent heat of fusion L (J/kg) =------------------------ f. mass M (kg) Or (rearranged) : E=m L f