Thermal Flashcards
What is heat?
The total kinetic energy within a system.
What is temperature?
The average kinetic energy of a particle within a system.
What is specific heat capacity?
The amount of energy needed to raise 1kg of a substance of 1 degree Celsius.
What is specific latent heat?
The amount of energy to change state of 1kg of a substance
What is brownian motion?
Movement of gas is random with random velocities.
What is proven by brownian motion?
atoms/observed particles are very small and their motion is random.
What are the gas laws?
Pressure law - Pressure is directly proportional to temperature (K)
Boyle’s Law - Pressure is directly proportional to 1/Volume, Temperature is constant.
Charles’s Law - Volume is directly proportional to temperature (K)
What is an isothermal process?
A process where temperature is constant.
What are the properties of ideal gasses?
- Particles occupy negligible volume compared to the volume of gas.
- Molecules are identical in mass and speed.
- Molecules collide with each other and the walls in a perfectly elastic matter in zero time.
- Molecules exert no force on each other except during collisions.
- There are enough molecules so that statistics can be applied.
- They are moving randomly and rapidly.
What is internal energy?
Sum of potential and kinetic energy.
How does a gas exert pressure on the walls of the container?
- Lots of molecules collide with the walls.
- Molecules change momentum
- Newton’s second law - resultant force is the rate of change of momentum therefore a force is exerted on the wall.
How to derive the relationship between absolute temperature and mean kinetic temperature?
PV = 1/3*Nmc^2
3PV = Nmc^2
KE = 1/2Mc^2
M = Nm
N = number of moles
m = Molar mass
2KE = Nmc^2
3PV = 2KE
3/2PV = KE
PV = KT for for one mol of gas
KE = 3/2kT
1/2mc^2 = 3/2kT
Kinetic Theory for solids
- Strong forces of attraction
- Particles tightly packed
- Vibrate about fixed positions
- High density
Kinetic Theory for liquids
- Medium forces of attraction
- Particles close
- Particles slide past each other
- Medium density
- Translational kinetic energy
Kinetic Theory for gas
- Almost no attractive forces
- Particles far apart (unless compressed)
- Free to move around quickly, randomly
- Low density, compressible
What is N?
Number of particles
What is n?
Number of moles.
What is the equation for the mass of an element?
M*n = m (in grams)
M = molar mass
n = number of mols
How do I calculate the energy supplied for an object to change state into liquid then into gas?
E = mc/\T + mL(fusion) + mc/\T + mL(vapourisation)
What happens to the maxwell-boltzmann curve when temperature is increased to an ideal gas?
Gases with higher temperatures have more particles with higher speeds. Therefore, peak of curve drops but curve is much less steep slope.
What is a boltzmann distribution curve?
Number of molecules against energy.
