P3 Flashcards
Density Equation?
p = m / v
Units for density
density, ρ, in kilograms per metre cubed, kg/m3
mass, m, in kilograms, kg
volume, V, in metres, cubed, m3
Internal Energy
Internal energy is the total kinetic energy and potential energy of all
the particles (atoms and molecules) that make up a system
How to calculate specific latent heat?
L = Energy needed for a change of state / mass
what does the increase in temperature depend on?
If the temperature of the system increases, the increase in
the temperature depends on the mass of the substance heated, the
type of material and the energy input to the system.
How to calculate the change in thermal energy?
change in thermal energy = mass × specific heat capacity × temperature change
Specific Heat Capacity
The specific heat capacity of a substance is the amount of energy
required to raise the temperature of one kilogram of the substance
by one degree Celsius.
Specific latent heat
The specific latent heat of a substance is the amount of energy
required to change the state of one kilogram of the substance with
no change in temperature.
What happens when a change of state occurs?
When a change of state occurs, the energy supplied changes
the energy stored (internal energy) but not the temperature.
How to calculate the energy for a change of state?
energy for a change of state = mass × specific latent heat
E = mL
Specific latent heat of fusion
change of state from solid to liquid
Specific latent heat of vaporisation
change of state from liquid to vapour
What is the temperature of a gas related to?
the average kinetic energy of the molecules.
What happens when you change the temperature of a gas?
Changing the temperature of a gas, held at constant volume, changes the pressure exerted by the gas.
What types of changes are changes of state?
Physical changes; they are reversible
During changes of state, does temperature increase?
No; the energy is being used to break the bonds between the particals
What happens as a substance increases in temperature?
Each particle gains kinetic energy and begins to vibrate with a bigger amplitude; the gain in kinetic energy causes the temperature to increase ( Specific Heat Capacity)
What happens during a change of state?
Once particles have gained enough kinetic energy, the thermal energy is used to break the bonds between the particles ( Specific Latent Heat )
Potential energy?
Potential the particles have to bond; the energy absorbed to break forces between particles
What state has the highest potential energy?
A solid; the particles have already formed bonds
If there is a change in temperature, what does that mean?
Kinetic energy is changing
If there is a change of state, what does that mean?
Potential energy is changing
What is pressure?
The impact/force exerted by gas molecules colliding with the container over a small space/area
What is gas pressure?
The total force exerted by by all gas molecules over the walls of the container
How to increase the pressure of a gas?
- Increase temp of gas
- Decrease the volume of the container
- Increase the number of particles in the container
Why does increasing temp increase gas pressure?
- Increase in temp = increase in kinetic energy
- particles move faster
- causing more collisions with the wall of the container
- more collisions = greater force
- = pressure increasing
What can be compressed and why?
- Gas, yes: Particles are far apart, able to move away from other particles
- Solid/Liquid, no: Particles can’t move further away from each other
Why do some objects float?
They have a lower density than the liquid
What increases density?
Salt
Why do cold things have heat?
Each molecule has some sort of heat energy, therefore a big cold thing would have more heat energy than a small thing since it has more molecules so it adds up
What do you need to increase heat energy?
More molecules
What is heat energy?
Total energy of all particles
What is temperature?
The kinetic energy of the average particle
