PARTICLE MODEL OF MATTER Flashcards
describe the particle structure in a solid
strong forces of attraction between particles which hold them in a fixed position, closely together to form a regular lattice structure.
Because the particles are fixed solids have a solid definite shape and volume. The particles vibrate in a fixed position
what happens when a solid is heated
The particles gain more kinetic energy and vibrate, even more, weakening the force between the particles, at the melting point, the particles have enough energy to break free from the bonds, so the solid melts into a liquid.
describe the particle structure of a liquid
weaker forces of attraction between the particles, so the particles move around at random directions at low speed, forming an irregular arrangement. The particles are closer together so they have a definite volume but they do take up the shape of the container
what happens when a liquid is heated
The particles gain more kinetic energy, weakening the forces between the particles when you reach the boiling point, the particles have enough energy to break the bonds so the liquid turns into a gas
what happens when a liquid is cooled
when you cool down a liquid, the particles won’t have enough energy to overcome the attraction between the particles, forming new bonds, freezing the liquid into a solid
describe the particle structure in a gas
no forces of attraction, particles have more energy so they are free to move at random directions at a high speed. They do not have a definite shape or volume, they take up the shape of the container because the particles are spread out.
what happens when a gas is heated
They gain more kinetic energy and expand the container or increase the pressure
what happens when a gas is cooled
When we cool gas, the particles won’t have enough energy to overcome the forces between the particles, so they will create new bonds, condensing the gas into a liquid
is a state of change a chemical change or physical change
physical change because you dont end up with new substances
is mass conserved in a closed system?
mass is conserved in a close system
what is density
density is the mass of a substance per unit of its volume
the formula for density, mass and volume
density = mass/ volume
1 g/cm^3 into kg/m^3
1 g/cm^3 = 1000kg/m^3
required practical = measuring the density of a regular solid
1) measure the mass of the solid using a balance and record it
2) measure its width, length and height using a ruler and calculate the volume using the correct formula for the shape
3) substitute the values you got for the mass and volume into the formula density=mass/volume, and calculate the density
required practical = measuring the density of an irregular solid
1) measure the mass of the solid using a balance and record it
2) Fill a eureka can with water up to the outlet, and place a measuring cylinder next to the outlet
3) submerge the irregular object into the eureka can, the water displaced from the object will be transferred to the measuring cylinder
4) Record the volume of the water in the measuring cylinder, this is the volume of the irregular object.
5) substitute the values you got for the mass and volume into the formula density=mass/volume, and calculate the density
required practical = measuring the density of a liquid
1) place an empty beaker on the balance and zero the balance
2) pour 10cm^3 of water into the beaker
3)measure the mass of the water by reading off the balance
4) substitute the values you got for the mass and volume into the formula density=mass/volume, and calculate the density
larger volume = more accuracy because it minimises the effects of uncertainty
what is internal energy?
the total amount of kinetic energy and potential energy of all the particles in a system
Why do particles have energy in their potential energy store?
particles have energy in their potential energy store because of their position
Why do particles have energy in their kinetic energy store
particles have energy in their kinetic energy store because particles vibrate or move around
what happens to the internal energy store when a substance is heated
heating a substance transfers energy to the kinetic energy store of the substance, increasing their internal energy so increasing their temperature
temperature
the measure of the average internal energy of a substance
relationship between more internal energy store of a substance and temperature
the more internal energy of a substance= higher temp
specific heat capacity
the total amount of energy needed to raise 1kg of a substance by 1-degree Celsus
specific heat capacity formula
change in energy (J) = m x sc (J/Kg °C) x change in temp ( °C)
why doesn’t the temperature increase during a change in state (heating)
During the melting or boiling point, the energy we provide is used to weaken or break the bonds holding the particles together instead of increasing the internal energy of the substance
why doesn’t the temperature increase during a change in state (cooling)
when cooling a substance, the state change involves the formation of new bonds between the particles. This releases energy which counteracts the cooling, keeping the temperature constant during the change of state
what is latent heat
the exact amount of energy required or released to change the state of a substance without changing its temperature
what is specific latent heat?
The amount of energy required or released to change 1 kg of a particular substance from one state to another without changing its temperature
what is the specific latent heat of fusion
energy change when a substance changes from a solid to liquid (freezing or melting)
what is the specific latent heat of vaporisation
energy change when a substance changes from a liquid to a gas (boiling, condensing)
what is the equation for specific latent heat
E (energy released or required) = m x L (specific latent heat - J/Kg)
How does a gas particle create pressure
a gas particle move about at high speed, when they collide with something they exert a force on it, creating pressure
what is pressure
force exerted per unit of an area
Total pressure depends on 2 things
how many collisions there are
how much energy each collision involves
factors affecting pressure
temperature, concentration and volume
how does temperature affect pressure?
heating a gas transfers energy to the particle’s kinetic energy store, this means that particles move around more quickly, increasing the number of collisions and each individual collision will have more force, increasing pressure
how does concentration affect pressure
increasing the number of particles but keeping the volume same means that particles will collide more often, increasing number of collisions, increasing pressure
how does volume affect pressure?
decreasing the volume means there are more particles per unit of volume. Because the particles don’t have far to travel between each collision, there will be more collisions, increasing pressure
pressure, force and area formula
pressure = force/ area
relationship between pressure and volume
pressure and volume are inversely proportional to each other
pressure x volume = constant (same) value
unit for pressure
pascal
