I have been attempting this problem so many times. I don't know if I am plugging in the numbers correctly but I cannot seem to get the answer correct. Please help! A patient arrives in the emergency room with a burn caused by steam. Calculate the heat, in kilocalories, that is released when 12.4 g of steam at 100. ∘C hits the skin, condenses, and cools to body temperature of 37.0 ∘C.
I attempted with (100∘C-37∘C)
12.4g*63∘C*540cal/g∘C= 421848cal*1kcal/1000cal= 421.9kcal
I'm not sure but isn't there supposed to be specific heat involved in there ?
(Sorry if it's a silly question, but i'm still a high school student)
To calculate the heat released when the steam condenses and cools to body temperature, you need to consider the phase change from steam to water and then the cooling of water from 100°C to 37°C.
First, let's calculate the heat required for the phase change from steam to water. This is done using the formula:
q = mass * heat of vaporization
The heat of vaporization for water is approximately 540 calories/gram. So, plugging in the values:
q = 12.4g * 540cal/g = 6696 cal
Now, we need to consider the cooling of the water from 100°C to 37°C. For this, we will use the formula:
q = mass * specific heat capacity * temperature change
The specific heat capacity of water is approximately 1 calorie/gram°C. Plugging in the values:
q = 12.4g * 1cal/g°C * (100°C - 37°C) = 12.4g * 1cal/g°C * 63°C = 783.6 cal
Finally, to find the total heat released, you add up the heat required for the phase change and the cooling:
Total heat released = 6696cal + 783.6cal = 7479.6 cal
Since the question asks for the answer in kilocalories, you divide the result by 1000:
Total heat released = 7479.6 cal * (1kcal/1000cal) = 7.4796 kcal
Therefore, the correct answer is approximately 7.48 kilocalories.