In a vessel with water, the mass of which is 20 kg, and the temperature is 0 ° C, water vapor was admitted

In a vessel with water, the mass of which is 20 kg, and the temperature is 0 ° C, water vapor was admitted at a temperature of 100 ° C. After some time, a temperature of 20 ° C was established in the vessel. What is the mass of water in the vessel at the end of the process? There is no heat exchange with the environment.

To solve the problem, we will use the following formula:
Q = Q1 + Q2 + Q3;
Let’s transform the formula:
Q = c * m * Δt + L * m + c * m * Δt;
Let’s substitute the values into the formula:
Q = 4200 * 20 * 20 + 2300000 + 4200 * 80;
Q = 1680000 + 2300000 + 336000;
m = 0.637 kg (steam mass after condensate);
m = 20 + 0.637;
m = 20.637 kg.
Answer: m = 20.637 kg.