Topic 3 - Particle Model Of Matter Flashcards
Density equation
Density(kg/m^3)= mass(kg) : volume(m^3)
What are the 3 states of matter?
Solid, Liquid and Gas
For each state of matter, describe the arrangement and movement of the particles.
Solid- Fixed, regular arrangement with particles only vibrating in their fixed positions.
Liquid- Particles are close together, but can move past eachother, and form irregular arrangements. The particles move in random directions at low speeds.
Gas- Particles are loose and in no particular arrangement with almost no forces of attraction between eachother. They are free to move, and travel in random directions at high speeds.
Practical:
Describe how you could find the volume of an irregular solid object.
- Use a balance to measure mass
- Submerge the object in a eureka can filled with water. The water displaced by the object is transferred to a measuring cylinder.
- Record the volume of water in the measuring cylinder. This is the volume of the object.
- Use the formula m=PV to find out the density.
Practical:
Briefly describe an experiment to find the density of a liquid.
- Place a measuring cylinder on a balance and zero the balance.
- Pour 10ml of the liquid into the measuring cylinder and record the liquid’s mass and volume.
- Pour another 10ml into the measuring cylinder and record the total volume and mass.
- Repeat until the measuring cylinder is full
- For each measurement, use the formula m=PV to find out the density.
- Finally take an average of the densities to get the accurate density for the liquid.
What is internal energy?
The total energy that the particles of a system have in their kinetic and potential energy stores.
What happens to the particles in a substance when that substance is heated?
They gain energy in their kinetic energy stores and move faster, which increases the internal energy.
Name the 5 changes of state
Solid -> Liquid (melting)
Liquid -> Solid (freezing)
Liquid -> Gas (boiling/evaporating)
Gas -> Liquid (condensing)
Solid -> Gas (sublimating)
Is a change of state a physical or a chemical change?
Physical change.
True or False? Mass stays the same when a substance changes state.
True
Explain the cause of the flat sections on a graph of temperature against time for a substance being heated.
Energy is being transferred by heating/cooling but not being used to change the temperature.
Define specific latent heat.
The amount of energy needed to change 1 kg of a substance from one state to another without changing it’s temperature.
What is meant by the term ‘specific heat of fusion’?
The specific latent heat for changing between a solid and a liquid(melting/freezing)
What is meant by the term ‘specific heat of vaporisation’?
The specific latent heat between a liquid and gas (evaporating/condensing).
What is meant by the term ‘specific heat of vaporisation’?
The specific latent heat between a liquid and gas (evaporating/condensing).
Explain how a gas in a sealed container exerts a pressure on the walls of the container.
As gas particles move about at high speeds, they bang into eachother and whatever else happens to get in the way. When they collide into the walls of the container they exert a force, and so a pressure, on it.
A sealed container of gas is kept at a constant temperature. The volume of the container is increased. What happens to the pressure of the gas? Explain why.
It decreases, because the particles get more spread out and hit the walls of the container less often.
For a fixed mass of gas at a constant temperature, what is the relationship between pressure and volume?
pV = constant
True or False? For a gas at constant temperature, increasing the volume of the gas will also increase its pressure.
False
A balloon containing a fixed mass of helium gas is moved from an area of high atmospheric pressure to one of low atmospheric pressure. What will happen to the volume of helium in the balloon?
It increases.
Explain why blowing up a football with a pump causes the ball to warm up.
The gas applies pressure to the plunger of the pump and so exerts a force on it. Work has been done against this force to push down the plunger. This transfers energy to the kinetic energy stores of the gas particles, increasing the temperature, so the football gets warmer.
