Question

5 kg block of iron is heated to 800°C. It is placed in the tub containing 2 L of water at 15°C. Assuming all the water is brought to the boil rapidly, calculate the mass of water which boils off. (The specific heat capacity of iron 800°C is 220 J kg-1 K-1)

Answer 1

Heat Loss = 5 kg * 700 deg K * 220 J / (kg*deg K) = 7.70E5 J

Since there are 4.186 J/cal

Heat Loss = 7.70E5J / 4.186 J/cal = 1.84E5 cal

Heat Gain = 2000 g * 85 deg K / cal / (deg K g) + M * 540 cal/g

Heat Gain = 1.70E5 cal + M * 540 cal/g

M = (1.84 - 1.70) E5 g / 540

25.9 g

25.9 g or 25.9 cm^3 or .0259 L of water will boil away