1.1. Define the first law of thermodynamics.

1.2. State the principle that the First Law of Thermodynamics is based on.

1.3. Figure 1 shows a gas in a cylindrical container with a movable piston. 

Figure 1

State two ways in which the internal energy of the gas can be: 

  (i) Increased 

(ii) Decreased

1.4. The piston can smoothly move up or down the cylinder but is held in place.

The piston is then released. Explain whether the work is done by the gas or on the gas if the piston moves: 

 (i) Upwards 

(ii) Downwards