partice model of matter

Explain arrangement of particles in solids

• Strong force of attraction hold particles very close together

• Arranged in a fixed, regular pattern

• Particles dont have much energy so vibrate around fixed positions

Explain arrangement of particles in liquids

• lower density than solids and

• weaker forces of attraction between particles

• Particles are close but can move around each other at a low speed

• Arranged irregular

• Particles have more energy

Explain arrangement of particles in gas

• low density

• No forces of attraction so Particles far apart

• Particles arranged irregular

• Move rapidly

What is density

Measure of compactness in a substance

Equation for density

Mass divide by volume

Experiment to find density of a regular shaped object

1. Use a balance to measure mass of object

2. Measure length and width and height with ruler

3. Calculate volume

4. Find density

Experiment to find density in an irregular object

1. Place object on balance to get mass

2. Submerge object into water, using a measuring cylinder

3. Measure amount of volume of water displaced which gives you volume of the object

4. Use density equation

What happens when temperature of gas increases

Average energy in kinetic energy of gas increases which increases speed

If a gas is kept at a constant volume what impact will temperature increase have

Increase the pressure

What is a physical change

A change where you dont end up with a new substance

What is internal energy

Energy stored in a system by its particles and total kinetic and potential energy of its particles

State two things that the increase in a systems temperature depends on

1. Specific heat capacity

2. Mass

What happens to internal energy if we heat something

Increases

What happens to internal energy if we decrease heat

Internal energy decreases

What happens to mass when change of state happens

Conserved

Specific heat capacity

Amount of energy required to raise the temperature of 1kg of a substance by 1 degree

What does DELTA E stand for specific heat capacity

Change in thermal energy (j)

What does m STAND FOR SHC

MASS- KG

What does c stand for specific heat capacity

Specific heat capacity (J/KG)

What does delta 0 stand for specific heat capacity

Temperature change

What is specific latent heat

Energy required to change state of 1kg of a substance with no temperature change

Specific latent heat of fusion

Energy needed to change solid to liquid with no temperature change

Specific latent heat of vaporization

Energy needed to change liquid to vapour with no temperature change

What does pressure of a gas depend on

• the particles colliding with walls of container its held in

• Temperature

• Speeed of particles

What happens if u increase pressure in a gas

Increase frequency of time it hits the wall of container (more collisions)

How to increase pressure

Increase temperature

What do particles with low temperature have

Lower kinetic energy so lower collisions with container and particles so lower pressure

What happens when a gas hs a high temperature

Particles have more kinetic energy so they move faster which increases collisions with particles and container its held in which increases pressure

What is the difference from physical and chemical changes

Physical changes are reversible and can originate back to original properties whereas chemical are not or it is hard to

What i a physical change and an example

• reversible and no new substance is formed

• Change of state

What is a chemical change

• a new substance is made from it

• Usually not reversible or hard to reverse

Specific latent heat equation

Q = M X L

WHAT DOES Q STAND FOR SPECIFIC LATENT HEAT

HEAT ENERGY

Evaporation

Liquid to gas

Condensation

Gas to liquid

Freezing

Liquid to solid

Melting

Solid to liquid

Sublimation

Solid to gas

Why does temperature increase of air inside a bike pump when pumped

• work is done Ona gas when compressed

• Which increases internal energy to average kinetic energy increases

• So temperature increases with increase of kinetic energy as more frequent collisions

What increases when work is done on a gas

Internal energy

Unit for pressure

Pascals - Pa

When water boils in a pan why does mass appear to decrease

• some water evaporates and turns to water vapour

• This leaves meaning mass of pan seem to decrease

• The mass of whole system will remain the same as mass is conserved

Explain process when bathroom mirror mists up

• hot water evaporates to form water vapour

• Water vapour lands on cooler mirror

• Vapour condenses and turns to liquid on mirror

What can heating do

• change state of a substance

• Raise temperature

• Raise kinetic energy and thermal energy and internal energy

What ae three factors determining temperature change of a system

• mass of a substance being heated

• Type of material (specific heat capacity)

• Energy in system

What does it mean if there have a higher temperature

Higher average kinetic energy of molecules So more frequent collisions

Why does pressure increase as temperature increases

• kinetic energy of molecules increase

• Speed of particles increase so collide more frequent

• Molecules will collide with surface of container creating a greater force leading to greater pressure

If gas at high pressure what des this mean

• particles will have high kinetic energy

• Lots of frequent collisions

• high temperature

If gas is at a low pressure, what does this mean for its particles

• fewer collisions

• Low temperature

• Less kinetic energy

What can be said about the product of pressure and volume for a fixed mass of gas at a constant volume

It is constant