Determine the change in the internal energy of a gas confined in a...

For a rigid container, the volume of the gas remains constant, so $\Delta V = 0$.

The work done by the gas is $W = P\Delta V = 0$.

According to the first law of thermodynamics, $\Delta Q = \Delta U + W$.

Given that the heat provided to the gas is $\Delta Q = 100 \text{ J}$.

Substituting the values, $100 = \Delta U + 0$.

Therefore, the change in internal energy is $\Delta U = 100 \text{ J}$.