Particle Model - Physics

When the kinetic energy of the particles in a substance increases, what happens to the substance?

Temperature increases

When the pressure inside a closed container is much bigger than the pressure outside the container, what can happen?

Explosion

When the pressure outside an open container is bigger than the pressure inside, what happens?

Air moves into the container

Complete this sentence: Decreasing the temperature of a gas …............... the gas pressure.

decreases

What symbol is used instead of writing the word 'temperature'?

ϴ (the Greek letter theta)

What symbol is used instead of writing the words 'specific heat capacity'?

c

What piece of equipment is used to measure length?

ruler

In what case would an object lose heat to the surroundings?

When the surroundings are colder than the object.

Why do substances have different melting points?

Different forces between particles

Define the specific latent heat of vaporisation of a substance.

Amount of energy needed to boil 1 kg of the substance with no change in temperature

At what temperature do melting and freezing take place for water?

0 ᵒC

State the unit of temperature.

degrees Celcius or ᵒC

Which state of matter is usually the least dense?

gas

When particles move faster, their …........... energy increases.

kinetic

Describe the arrangement of particles in a liquid.

Closely packed, not regular arrangement

What causes gas pressure?

Collisions of particles

Why does ice melt faster when placed on most metals than on most non-metals?

Metals are better conductors of heat

in what case would an object absorb heat from the surroundings?

When the surroundings are hotter than the object.

What is volume?

The amount of space an object fills

Why do substances expand when heated?

The particles gain kinetic energy and move further apart

How can gas turn to liquid without increasing temperature?

Increasing pressure

What is a system?

A group of interacting parts

What happens to the density of a substance when it is heated and expands

Decreases

State the equation linking density, mass and volume.

Mass = density x volume

Which state(s) of matter can be compressed?

gas

Are changes of state physical or chemical changes?

physical

What name is given to the total kinetic and potential energy of all the particles in a system?

Internal energy

When the pressure inside an open container is bigger than the pressure outside, what happens?

Air moves out of the container

Why do liquids and gases take the shape of their container?

The particles can move around

What piece of equipment is used to measure the volume of a liquid?

Measuring cylinder

At what temperature do boiling and condensing take place for water?

100 ᵒC

When a force decreases the volume of a substance the substance has been …

Compressed

In the particle model of matter, what are 'particles'?

Atoms, molecules or ions

What name is given to the mass per unit volume of a material?

density

When particles move further apart, their …................ energy increases.

potential

What symbol is used instead of writing the word 'volume'?

V

Why don't solids take the shape of their container?

The particles can't move around

Name the state change: Solid to gas.

Sublimation

At what temperature do melting and freezing take place?

The melting point

Describe the forces between particles in a liquid.

Weaker than in a solid

Name the state change: Liquid to gas.

Boiling

How do you convert from cm³ to m³?

÷ 1,000,000

How do you convert from g into kg?

÷ 1000

On a cooling or heating curve, what is happening in the horizontal sections?

Change of state at constant temperature

Describe the motion of the particles in a gas.

Move freely and randomly with a range of speeds and directions

What symbol is used instead of writing the word 'density'?

ρ (the Greek letter rho)

At what temperature do boiling and condensing take place?

The boiling point

What piece of equipment is used to measure temperature?

Thermometer

Why is mass conserved during state changes?

No particles are added or taken away

Why can't liquids and solids be compressed?

There isn't space between the particles

Complete this sentence: Increasing the temperature of a gas …............... the gas pressure.

increases

The force exerted by particles in a gas colliding with each other and the walls of the container causes …

Gas pressure

Why are solids usually denser than liquids and gases?

More particles per unit volume

Why can't solids flow?

The forces between particles are too strong so the particles can't move around

What symbol is used instead of writing the word 'energy'?

E

Describe the arrangement of particles in a solid.

Closely packed, regular arrangement

Latent heat of vaporisation relates to which state change?

Liquid to gas OR boiling

What is evaporation?

The change from liquid to gas below the boiling point

In what 3 ways can gas pressure be increased?

Smaller volume, higher temperature, more particles

State the unit of density

kg/m³ or kilogram per cubic metre

Why are solids usually the best conductors of heat and electricity?

The particles are closely packed

What symbol is used instead of writing the word 'mass'?

m

Why does ice melt faster when placed on a surface which is a better conductor of heat?

Heat transfers to the ice faster

Which part of internal energy relates to changes of state?

Potential energy

Why can liquids and gases flow?

The forces between particles are weak enough for the particles to move around

What symbol is used instead of writing the word 'change'?

△ (the Greek letter delta)

Describe the forces between particles in a gas.

Almost zero

Name the state change: Liquid to solid.

Freezing

Describe the arrangement of particles in a gas.

Far apart

Which state of matter: Particles close together and can move over each other.

liquid

Explain why increasing the temperature of a gas increases the gas pressure.

Particles have more kinetic energy and move faster so collide more often with a greater force

What piece of equipment is used to measure mass?

Mass balance

Name the state change: Gas to liquid.

Condensing

On a cooling or heating curve, what is happening in the sloping sections?

Change of temperature

Which state of matter: Particles closely packed and vibrate on the spot.

Solid

Define the specific heat capacity of a substance.

Amount of energy needed to increase the temperature of 1 kg of the substance by 1 ᵒC

Why do hotter fluids rise above colder fluids?

Hotter fluids are less dense than colder fluids

Which state changes can occur when a substance is heated?

Melting and boiling

Latent heat of fusion relates to which state change?

Solid to liquid OR melting

Describe the forces between particles in a solid.

strong

Define the specific latent heat of fusion of a substance.

Amount of energy needed to melt 1 kg of the substance with no change in temperature

Name the state change: Solid to liquid.

Melting

Which state of matter is usually the most dense?

solid

Describe the motion and kinetic energy of the particles in a solid.

Vibrate about fixed positions, low kinetic energy

State the unit of energy.

joules OR J

Are changes of state reversible or irreversible?

Reversible

What is conserved during changes of state?

mass

State the equation linking density, mass and volume using symbols.

m = ρV

Why can gases be compressed?

There is space between the particles

Define internal energy

The total kinetic and potential energy of all the particles in a system

Which state changes can occur when a substance is cooled?

Condensing and freezing

When the pressure outside a closed container is much bigger than the pressure inside the container, what can happen?

Implosion/collapse

When a substance is heated and increases in temperature without changing state its particles gain …............... energy.

kinetic

Describe the motion and kinetic energy of the particles in a liquid.

Move around, higher kinetic energy than in a solid

Which state of matter is usually the best conductor of heat and electricity?

solid

Which state(s) of matter can flow?

Liquid and gas

How is density related to floating?

Less dense substances float on more dense substances

Describe the kinetic energy of the particles in a gas.

high

The energy needed to increase the temperature of 1 kg of a substance by 1 ᵒC is called the …

Specific heat capacity

Define density.

Mass per unit volume