Question

Consider a 2 mole sample of helium at 22 degrees celsius, which occupies the volume of 22.9 dm3 assume helium behaves perfectly. calculate w, q delta u. when the guest expands ice with family at zero external pressure until its volume 31.7 dm3,

Answer 1

To calculate the work done (w), use the formula w = -PΔV, where P is the pressure and ΔV is the change in volume. For the given problem, the work done (w) is 0 since the expansion is done at zero external pressure. The heat transferred (q) can be calculated using the formula q = ΔU + w.

Step-by-step explanation:

To calculate the work done (w), we can use the formula w = -PΔV, where P is the pressure and ΔV is the change in volume. In this case, the pressure is zero because the expansion is done at zero external pressure. So, w = 0. The heat transferred (q) can be calculated using the formula q = ΔU + w, where ΔU is the change in internal energy. Since the helium behaves perfectly, its internal energy only depends on temperature, and can be calculated using the formula ΔU = nCΔT, where n is the number of moles, C is the molar heat capacity, and ΔT is the change in temperature.


The molar heat capacity at constant volume (Cv) for helium is 3R/2, where R is the gas constant. The final step is to calculate the change in volume (ΔV) using the ideal gas law, PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the gas constant, and T is the temperature. Substituting the given values into the equation and solving for ΔV will give the answer.