An insulated beaker with negligible mass contains 0.250 kg of water at 75.0o C. How many kilograms of ice at - 20.0o C must be dropped into the water to make the final temperature of the system 40.0o C?

Solution 57E Step 1 Let us consider the mass of the ice is m. The heat released by water is given by 4 Q w m c w w (0.250 kg)(4190 J/kg · °C)(75°C 20°C) = 5.76 × 10 J