particle model of matter - particle motion in gases Flashcards
how do particles in a gas move
with random direction and speed
- far away from each other
how does the temperature of a gas relate to the average energy
the higher the temperature, the higher the average kinetic energy
what happens when gas particles move at a high speed
- they bang into each other and exert a force
- faster particles means more frequent collisions
what factors increase / decrease gas pressure in a container
- increasing temperature will increase the speed, and so the pressure ( if volume is kept constant )
- if temperature is constant, increasing volume means particles get more spread out and will hit container walls less often, decreasing pressure
what is the relationship between volume and pressure
they are inversely proportional, increasing volume decreases pressure, decreasing volume increases pressure
what is the equation for pressure and volume for a gas of a fixed mass at a constant temperature
pV = constant p= pascals ( Pa ) v = volume ( m ^ 3 )
equation for change in momentum
The change in momentum is equal to the force multiplied by time. It is also the same as impulse
how to find pressure
force/ area
how does the speed of particles in a gas differ from ones in a solid or liquid
they are quicker than ones in a solid or liquid
what happens if you increase the volume of a gas in a container
increasing the volume in which a gas is contained, at constant
temperature, can lead to a decrease in pressure.
Describe gas particles in a container
Since the particles in a gas are moving fast and randomly, collisions occur frequently. These collisions may be between two particles, between a particle and the wall of the container, or between a particle and something else in the container.
For example, the collisions caused by a gas trapped inside a balloon cause forces to act outwards in all directions, giving the balloon its shape.
why might the pressure of gas molecules increase
The pressure from gas molecules may increase if there are more molecules colliding each second or if the molecules are moving faster.
what happens if the volume of gases inside a container stays the same
the pressure of a gas increases as its temperature increases. (directly proprtional)
If the temperature of a gas stays the same, the pressure of the gas increases as the volume of its container decreases…why?
This is because the same number of particles collides with the walls of the container more frequently as there is less space. However, the particles still collide with the same amount of force.
what is work
the transfer of energy by a force
what happens when you do work on a gas
Doing work on a gas increases the internal energy of the gas and can cause an increase in the temperature of the gas.
work done equation
force x distance
work done equation
force x distance
what does mechanical work do
transfers energy from the person or machine’s store of chemical energy to the internal energy store of the gas.
why does a bicycle pump get warm when its used to inflate a tyre
Since the volume of the gas has decreased, the pressure increases because the particles are moving in less space and collide more often. The temperature of the gas is not fixed in most applications and the increased pressure leads to an increase in temperature. This is because the temperature is a measure of the average kinetic energy of particles - the increase in the internal energy of the gas means that the temperature must increase.
what is the pressure of a gas due to
the particle’s colliding with the walls of the container that the gas is held in
how to increase gas pressure
- increase the number of collisions per second
- increase the energy of each collision
- increase the temperature of the gas
what happens to gas pressures at high temperatures
- at high temperatures, particles have higher kinetic energy
- meaning there are more collisions per second
- these are higher energy collisions
what do particle collisions cause
a force which acts at right angles to the walls of the gas container
- this force, acting over the area, causes the gas pressure
why does pressure decrease if volume increases and temperature is kept constant
- because we have now increased the spacing between the particles
- so now the particles can travel much further before colliding with the walls of the container and each other
- this reduces the number of collisions per second between the walls of the container and particles, reducing the pressure
whats the relationship between pressure and volume
they are inversely proportional, as one increases, the other decreases
