States of matter

In solids, particles are arranged in a regular order

- Particles are tightly packed together

- They have strong bonds which prevent it being able to change shape or volume

In liquids, the particles are arranged more randomly but are still quite tightly packed

- The bonds are weaker than in solids

-They can change shape

In gases, particles can move around freely 

-They have almost no bonds

-They can change shape and volume

Deposition = A gas turning directly into a solid

Sublimation = A solid turning directly into a gas

When you heat a substance, you give its particles more energy, and so it is more likely for the bonds to break apart

When you cool a substance, the particles have less energy and bonds can form

Melting point = The temperature at which a solid turns into a liquid (Water is 0)

Boiling point = The temperature at which a solid turns into a lquid (Water is 100)

Evaporation is also where a liquid turns into a gas - 

Boiling = occurs through liquid only whereas Evaporation = occurs on the surface only

During evaportation, the particles moving around on a liquid surface have enough energy to break away and leave the liquid; becoming gas particles

Only the particles with the most energy are able to do this, and so the average energy of the liquid is reduced, and it cools down. 

The larger the surface area, the greater the evaporation

Evaporation is also faster if the liquid is warmer, because there are more particles with energy to break away. 

Also happens faster if there is wind over the surface of the liquid, as this increases the energy of the particles, and make it more likely for them to break away

The temperature of an object depends on the kinetic energy of the particles which make up the object - If the particles are hot, then they are moving quickly, and if the particles are cold, they are moving slower.

The average speed of hotter objects is higher than colder:

- The molecules in a hot cloud of gas will move faster than the molecules in the same cloud of gas at a lower temperature. 

The densitys of liquids and solids are similar as they both have quite tightly packed particles: Gases have a much lower density. Densitys:

Aluminium (Solid) = 2700kg/m // Water (Liquid) = 1000kg/m // Air (Gas) = 1.3kg/m

Because both liquids and gases can change their shape, they are reffered to together as fluids. 

Density is a measure of how big something is and how heavy something is combined

Mass = How much matter in an object: always stays the same

Weight = Force due to gravitational pull of gravity: changes depending on gravitational field

Density =

Heat = thermal energy in motion moving from one body to another - measured in joules (j)

Temperature = a measure of thr average kinetic energy; the hotter the object, the faster the particles move

 2 beakers both with the same volume and temperature of water will contain equal amounts of thermal energy 

Thermal energy always moves from a hotter body to a colder body, also in the opposite direction. 

The bigger the temperature difference, the faster transfer of thermal energy

If a human stands in a temperature that is too cold, they will lose thermal enegry at a faster rate and their internal body temperature will decrease

The rate of heat loss depends on volume and surface area

If you take two objects that have equal masses and volumes, but are made up of two different materials, and supply both objects with the same amount of thermal energy, then their final temperatures will not neccesarily be the same

Specific heat capactiy = The measure of the materials ability to absorb thermal energy, and a measure of the heating effect of thermal energy on the material 

Specific heat capacity = J/kg-k

E.g Water = 4200J/kg-k

Therefore, to raise the temperature of 1kg of water by 1 kelvin (k) requires 4200J of thermal energy: To raise the temperature of 1kg by 2 kelvin would require 8400J of thermal energy.

Specific heat capacity is equal to the thermal energy supplied to the substance

                                                           Mass X Change in temperature

Q=mcΔθ

Q is the thermal energy supplied (J)

M is the mass of the substance being heated (kg)

C is the specific heat capacity (J/kg-K)

Δθ is the change in temperature (°C/K)

Thermal energy required is proportional to the other quantities, so doubling the mass, or the specific heat capacity, or changing the temperature results in a doubling of thermal energy required

The amount of energy required to change the state of a substance (the latent heat) varies between substances 

2 types of latent heat: Latent heat of fusion - thermal energy required to change a solid to a liquid or a liquid to a solid

& Latent heat of vaporisation is the thermal energy required to turn a gas into a liquid, or a liquid into a gas.

If the energy of the substance is increasing - solid to liquid or liquid to gas, then thermal energy must be transferred into the substance

If the thermal energy is decreasing - gas to liquid or liquid to solid, then more thermal energy must be transferred out of the substance.

The amount of latent hear doesn't change with different changes of state, it takes the same amount of energy to turn 1kg of ice into water, as it does to turn 1kg of water into ice

Changes of state occur at constant temperatures

e.g water at 100°C changes to steam at 100°C

The latent heat of a substance is measured in joules per kilogram (J/kg)

The kinetic theory is the theory of matter that explains solids, liquids and gases as being composed of tiny particles that move

The temperature of an object is a measure of the average kinetic energy of the particles that make up the object - the faster the particles move, the hotter the object is: At absolute zero, -273 (coldest possible temperature) this movement is at its minimum - stationary particles

Substances change state as their temperature increases.

Changing from solids to liquids to gases

Of the 3 states of matter, gases have the most kinetic energy as the particles in a gas are free to move around at high speeds. 

Liquids have less kinetic energy as the particles are more tightly packed and therefore cant move around as much, or very fast

Solids have the least kinetic energy.

Of the 3 states of matter, gases have the most kinetic energy as the particles in a gas are free to move around at high speeds. 

Liquids have less kinetic energy as the particles are more tightly packed and therefore cant move around as much, or very fast

Solids have the least kinetic energy.

As a solid is heated, its particles vibrate faster and eventually the particles are able to break out of their tight arrangement, and the bonds between them weaken. The solid becomes a liquid. 

As a liquid is heated, its particles vibrate more and faster until the bonds break, then the liquid becomes a gas

As a material heats up and the particles move faster and faster, the bonds increase in length and the material expands in size. Because the number and mass of the particles don't change, the means the density will decrease.

Conduction occurs mainly in solids and is due to collisions between tightly packed particles, and the movement of free, delocalised electrons. 

The collisions between the particles and the electrons cause the transfer of kinetic energy along and through the material until the entire material is at the same temperature.

Pressure =- how much force is exerted on a certain area. Force per unit area

P=F/A

Unit of pressure = pascal (Pa)

1 pascal = 1 newton per square meter

The bigger the force, the higher the pressure, also the smaller the area the higher the pressure.

Weight acts downwards.

Gas pressure is caused by particles colliding and bouncing off things

Particles in gases are not joined together, they can move randomly

Pressure is increased when the number of collisions increase

Collisions can increase when you have more particles in a smaller volume

At a constant temperature, pressure increases when the volume decreases, and the pressure decreases when the volume increases.

This is called boyle's law

P1 x V1 = P2 x V2

Increasing the temperature of a gasincreases the kinetic energy of the particles, making them move faster, and occupy more space

This means the volume of the gas would increase if pressure stayed the same

At a constant pressure, increasing the gas temperature increases the volume. This is called Charles' law.