5.1 Thermal Flashcards
Thermal equilibrium
When two objects at the same temperature so no heat flows between them
Absolute zero temperature
The temperature at which the internal energy of a system is at its lowest possible value
What is 0 degrees in Kelvin
273K
What is the relationship between absolute temperature and the average KE of particles in a substance?
Absolute temperature is proportional to average kinetic energy of the particles in a substance
What is the triple point of a substance?
The temperature and pressure at which a substance can exist in all three phases in thermal equilibrium.
Describe the kinetic model of a solid.
A regular arrangement of particles that are strongly attracted to each other. Particles vibrate but can’t change positions in the structure.
Describe the kinetic model of a liquid
Particles are attracted to each other but are free to move around
Describe the kinetic model of a gas.
Particles are far apart and there are no forces of attraction between them
What is the internal energy of a substance?
The sum of the randomly distributed kinetic and potential energy of the particles in an object
Why doesn’t the temperature of a substance change whilst it is changing state?
The electrostatic potential of the particles is changing rather than the kinetic energy.
Why is the electrostatic potential energy of liquids and solids negative?
Energy must be supplied to the substance to break the bonds between particles.
What effect does increasing the temperature have on the particles in a substance?
It increases their average kinetic energy.
What is the specific heat capacity (c) of a material?
The energy needed to raise the temperature of 1kg of the material by 1 degree Celsius/Kelvin without any change of state.
What are the units of specific heat capacity (c)
J kg^−1K^−1
What is ∆Q in ∆Q = mc∆θ
Thermal energy gained (or lost if negative) by an object (provided no change in state).
