Question

A sample of 2.50 kg of water is held at a temperature of 100°C. How much energy must be added to completely turn the liquid water to water vapor? (The latent heat of vaporization for water is 2260 kJ/kg; the latent heat of fusion for water is 333 kJ/kg.) A. 904 kJ B. 833 kJ C. 133 kJ D. 5650 kJ

Answer 1

Answer:

D. 5650 kJ

Explanation:

The given information from the exercise is:

- Mass of water (m): 2.50kg

- Temperature of water (T): 100°C

- State of water: liquid

During the process of change of state from liquid to gas, the temperature remains constant, that is, it does not change, in this case, the phase change will always be at 100°C.

Since water changes from liquid state to a gaseous state, we need to use the values of latent heat of vaporization of the water (lv: 2260 kJ/kg) and the mass of the water (2.50kg), to calculate the energy that must be added in the process:

$\begin{gathered} Q=m*l_v \\ Q=2.50kg*2,260\frac{kJ}{kg} \\ Q=5,650kJ \end{gathered}$

So, 5,650kJ must me added.