At a constant pressure of 1 MPa, helium expanded from 12 liters to 22 liters. How much heat was transferred to helium.

These tasks: P (constant helium pressure) = 1 MPa (1 * 10 ^ 6 Pa); V1 (initial volume of helium) = 12 liters (in SI V1 = 12 * 10 ^ -3 m3); V2 (final volume) = 22 l (in SI V2 = 22 * 10 ^ -3 m3).

Constants: i (number of degrees of freedom of helium molecules) = 3.

The amount of heat transferred to helium during expansion is determined by the formula (isobaric process): Q = ΔU + A = 0.5 * i * P * ΔV + P * ΔV = P * (V2 – V1) * (0.5 * i + 1).

Let’s perform the calculation: Q = 1 * 10 ^ 6 * (22 * 10 ^ -3 – 12 * 10 ^ -3) * (0.5 * 3 + 1) = 25 * 10 ^ 3 J (25 kJ).