Dry, saturated steam from a turbine enters a condenser at 4 kPa and exits as saturated liquid, also at 4 kPa. In the condenser, energy is removed from the steam by heat transfer to a stream of lake water. The lake water enters at 5° C and is then returned to the lake at 10° C (the maximum allowed by local regulations). Determine the mass of lake water required per mass of steam condensed.