Question

An ideal gas is confined within a rigid container with a fixed lid. The container is placed on a heat source. Which of the following correctly compares the force exerted on the lid by the ideal gas and the force exerted on the ideal gas by the lid, and correctly relates the force to pressure?

a) Force on the lid > Force on the gas; Pressure on the gas > Pressure on the lid
b) Force on the lid = Force on the gas; Pressure on the gas = Pressure on the lid
c) Force on the lid < Force on the gas; Pressure on the gas < Pressure on the lid

Answer 1

The force exerted by an ideal gas on the rigid container lid is equal to the force exerted by the lid on the gas, and thus the pressure is the same on both, which is explained by Newton's third law of motion and ideal gas laws.

Step-by-step explanation:

When an ideal gas is heated in a rigid container, the force exerted on the container walls (or the lid) by the gas is equal to the force exerted by the walls (or lid) on the gas, according to Newton's third law of motion. This means that each collision of a gas molecule with the container wall results in an equal and opposite reaction. Since the container is rigid, its volume does not change, and therefore, the pressure increases when the gas is heated due to the increase in the kinetic energy of the gas molecules. The gas laws, including Boyle's law and the ideal gas law, help explain these dynamics, indicating that the correct answer is (b) Force on the lid = Force on the gas; Pressure on the gas = Pressure on the lid.