# Latent Heat: 180kcal Lost in 30 Min, How Much Water?

• geah
In summary, the question asks for the amount of water lost during exercise, which can be determined by calculating the amount of heat given off through evaporation and using the latent heat of evaporation. The latent heat of evaporation is equal to 540 cal/gm.
geah

During exercise a person may give off 180kcal of heat in 30 min by evapouration of water from the skin. How much water is lost?

If someone could clearly explain the question that would be great thanks

When water evaporates, a certain amount of heat is needed to transform the water to vapour at the same temperature. The amount of heat necessary per unit mass is called the latent heat of evaporation and is equal to 540 cal/gm.

When a person sweats, the water evaporates, and the latent heat is supplied by the body of the person, thus cooling the body.

## 1. What is latent heat?

Latent heat is the amount of energy required to change the state of a substance without changing its temperature. It is the energy that is absorbed or released during a phase change, such as melting or boiling.

## 2. Why is 180kcal of latent heat lost in 30 minutes?

The amount of latent heat lost is dependent on the amount of water present and the temperature difference between the water and its surroundings. In this case, 180kcal may be lost due to the water being exposed to a colder environment, causing it to lose heat and potentially freeze or evaporate.

## 3. How much water is involved in the 180kcal loss of latent heat?

The amount of water involved in the loss of 180kcal of latent heat would depend on the specific heat capacity of the water, which is the amount of energy required to raise the temperature of one gram of water by one degree Celsius. Without this information, it is difficult to determine the exact amount of water involved.

## 4. Is the loss of latent heat reversible?

Yes, the loss of latent heat is reversible. If the temperature of the environment surrounding the water were to warm up, the water could potentially regain the lost latent heat and change back to its original state.

## 5. How does the loss of latent heat affect the properties of water?

The loss of latent heat can affect the physical properties of water, such as its state (solid, liquid, or gas). It can also affect the density and volume of the water, as well as its ability to dissolve other substances. Additionally, the loss of latent heat can have an impact on the overall energy balance of the surrounding environment.

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