Question

How much heat does 0.100 kg of water at the boiling point need to absorb in order to vaporize completely?

How much heat does 5.00 kg of water at 0°C need to give off in order to freeze completely?
How much heat must be taken away from 3 kg of water at the melting point for it to fully freeze?

Answer 1

To vaporize 0.100 kg of water at the boiling point, 225.6 kJ is required. To freeze 5.00 kg of water at 0°C, 1670 kJ is required, and for 3 kg of water to freeze, 1002 kJ is required.

Step-by-step explanation:

To calculate the heat required to vaporize water at the boiling point, we use the equation Q=mc where m is the mass of the water, and c is the heat of vaporization (2256 kJ/kg). So for 0.100 kg of water, Q = (0.100 kg)(2256 kJ/kg) = 225.6 kJ.

The heat required to freeze water at 0°C is calculated using the equation Q = mc, with m being the mass of the water, and c being the latent heat fusion of water (334 kJ/kg). For 5.00 kg of water, Q = (5.00 kg)(334 kJ/kg) = 1670 kJ. Likewise, for 3 kg of water, Q = (3 kg)(334 kJ/kg) = 1002 kJ.