Question

В бак с водой по трубе поступает 1 кг стоградусного пара. После конденсации пара температура воды в баке возросла на 35С. Если вместо пара поступит 1 кг стоградусной воды, то температура воды в баке возрастёт только на 5С. Объясните, почему степень нагрева воды различна.

Answer 1

Если стоградусный пар конденсируется, то он превратится в стоградусную воду, при этом конденсируясь, пар отдаёт энергию и нагревает бак с водой, а только потом этот уже подогретый бак начнёт нагревать стоградусная вода.
Во втором случае в бак налили просто стоградусную воду, поэтому бак нагрелся слабее (он не получил энергию от пара).

Answer 2

Explanation of the Temperature Change

When 1 kg of steam at 100°C condenses in the water in the tank, it releases a large amount of heat, causing the temperature of the water to rise significantly. On the other hand, when 1 kg of water at 100°C is added to the tank, it only increases the temperature slightly.

Reason for the Difference in Temperature Change

The reason for the difference in the temperature change lies in the latent heat of vaporization. When steam condenses into water, it releases the latent heat of vaporization, which is a large amount of heat energy. This additional heat energy causes a significant increase in the temperature of the water in the tank.

On the other hand, when water at 100°C is added to the tank, it does not undergo a phase change, so it does not release the latent heat of vaporization. As a result, the temperature of the water in the tank increases only by a small amount.

Conclusion

In summary, the difference in the temperature change when 1 kg of steam versus 1 kg of water at 100°C is added to the tank is due to the release of latent heat of vaporization during the condensation of steam, which results in a much larger increase in temperature compared to adding water at the same temperature.

I hope this explanation helps! If you have any further questions or need clarification on anything, feel free to ask.