Thermal Physics

Give the 2 ways that energy can transfer.

Work is done on one object by another

A temperature difference between the objects

What is the Internal Energy of an object?

The sum of the random distributions of the Kinetic Energy and Potential Energy of its molecules. An object has IE due to the position of the molecules and their movement.

What changed can we make to the system to increase the IE of an object?

If we transfer energy into the object via heating, or work is done on the object.

What does it suggest if IE stays constant?

No energy is transferred via heating, or No work has been done on the object

What is the first law of thermodynamics?

The change in IE of an object = the total energy transfer due to work done and heating

What happens to the IE if you increase the PE or KE?

The IE increases

What is the correlation between temperature and IE?

The greater the IE, the greater the temperature

What does it mean if two objects are at thermal equilibrium?

They are at the same temperature, and no energy transfer will take place by heating

Explain why when a hot object and a cold object are placed next to each other, they reach thermal equilibrium eventually

Energy is transferred from the hotter object to the colder object and also the surroundings, until the temperature of both objects are the same as the room temperature.

What is the triple point?

273K, when water exists as solid, liquid and gas

Explain how you can use a graph of pressure and temperature to find absolute zero.

At absolute zero, the object has 0 IE, so if the pressure of the gas is plotted against temperature, we will get a linear relationship. If you extrapolate this line back to the x (temp) axis, then it will always give the value of absolute zero as -273C, as the pressure at absolute zero is zero. (the molecules arent moving hence there are no collisions between molecules and the walls of their containers)

What is the definition of Specific Heat Capacity?

The energy needed to raise the temperature of a unit mass of the substance by 1⁰C, without changing the state of the substance

Describe a method using an inversion tube to find the specific heat capacity of lead