How many kcal of heat energy are removed from the body with every 1 L of sweat?
q = 1000 g x heat vaporization at 37 C in cal/g. Convert to kcal.
The amount of heat energy removed from the body with every 1 L of sweat can vary depending on various factors such as environmental conditions, individual metabolic rates, and activity levels. On average, sweating can remove approximately 580-600 kcal of heat energy per liter.
To determine how many kcal of heat energy are removed from the body with every 1 L of sweat, we need to understand the concept of specific heat capacity and the latent heat of vaporization.
1. Specific heat capacity (C): This is the amount of heat energy required to raise the temperature of a substance by 1 degree Celsius. The specific heat capacity of water is approximately 1 calorie per gram per degree Celsius (cal/g°C).
2. Latent heat of vaporization (L): This is the amount of heat energy required to convert 1 gram of a substance from a liquid to a gas at a constant temperature. For water, the latent heat of vaporization is approximately 540 calories per gram (cal/g).
Now, let's calculate the heat energy removed with 1 L of sweat:
1. Convert 1 L of sweat to grams. The density of water is approximately 1 g/mL, so 1 L of water is 1000 grams.
2. Calculate the heat energy required to raise the temperature of 1000 grams of water by 1 degree Celsius. Using the specific heat capacity formula: Heat energy (Q) = mass (m) x specific heat capacity (C) x temperature change (ΔT).
Assuming a typical body temperature of 37°C and ambient temperature of 25°C, the temperature change (ΔT) is 37°C - 25°C = 12°C.
Heat energy (Q) = 1000 g x 1 cal/g°C x 12°C ≈ 12000 calories or 12 kcal.
3. In addition to the heat energy required for raising the temperature, there is also the heat energy required for the phase change from liquid sweat to water vapor. Since we're assuming that the sweat completely evaporates, we need to calculate the latent heat of vaporization.
The latent heat of vaporization for water is approximately 540 cal/g.
Heat energy (Q) = 1000 g x 540 cal/g ≈ 540000 calories or 540 kcal.
Therefore, the total heat energy removed from the body with every 1 L of sweat is approximately 12 kcal + 540 kcal = 552 kcal.