Thermal Physics Flashcards
What is the SI unit of temperature?
K
What is the absolute zero temperature?
The lowest possible temperature an object can theoretically have
What is the value of absolute zero temperature?
0K (-273°C)
Describe the kinetic energy of molecules in an object at absolute zero temperature
They have no kinetic energy - so everything would stop
What do molecules have more of at higher temperatures?
They have more energy
In Kelvin scale, what 2 things are proportional to each other?
A molecule’s energy is proportional to the temperature
What is a change of 1K equal to in °C?
A change of 1°C
How do you convert from Kelvin to °C?
Minus 273°C
What is 0°C equal to in Kelvin?
273K
What is 100°C equal to in Kelvin?
373K
What can be said about particles in a gas, and what this depends on
All particles travel at different speeds, which is dependent on temperature (most travel at average speed)
What 3 things happen when the temperature of a gas is increased?
The average particle speed increases
The average KE of the particles increases
The distribution of speeds of particles becomes more spread out
What is the internal energy?
Internal energy of a body is the sum of the randomly distributed kinetic and potential energies of all its particles
What is a closed system?
A system which doesn’t allow any transfer of matter in or out
Describe the total internal energy for a closed system
It is constant, as long as it’s at a constant temperature and no energy is transferred in or from the system
What is transferred in a system when particles collide?
Energy is transferred between colliding particles almost constantly, but the total combined energy of all the particles doesn’t change
The average speed of particles in a system will stay the same provided that…?
The temperature of the closed system stays the same and no work is done on the system
How can the internal energy of a system be increased?
By doing work on the system by either heating or changing the systems shape
What happens to the average speed of the particles if work is done on the system?
The average speed will increase
How can the internal energy of a system be decreased?
By doing work to remove energy or by cooling
Describe what happens to the particles in a system if the internal energy decreases
The average kinetic or potential energy of the particles will decrease as a result of energy being transferred out of the system
Describe how heat is transferred
Heat is transferred from hot to cold
What is the difference between heat and temperature?
Heat is the total energy of molecules in a substance while temperature is a measure of the average energy of molecules in a substance
Describe how heat is transferred, in terms of particles
The particle with more energy transfers energy to the particle with less energy