One kg of water is placed in a piston–cylinder device initially at P = 1 bar and T = 5 ◦C. The density of water at this temperature is ρL = 1000.4 g L . The water is heated a constant pressure to T = 95 ◦C, whereupon the density is ρL = 962.3 g L . The external pressure is maintained at 1 bar.

(a) Calculate ∆U, Q, and W for this process. (b) Calculate Q under the assumption that density is constant, and that Cˆ V ≈ Cˆ P = 4.19 J g·K . (c) How well does the approximation work?