A slice of bread contains about 125 kcal.If specific heat of a person were 1.00 kcal/kg⋅°C,by how many °C would the temperature of a 65.0-kg person increase if all the energy in the bread were converted to heat?
A)3.85°C
B)0.96°C
C)1.92°C
D)2.40°C
E)1.44°C

Question

Quizplus · Accepted Answer

The amount of energy in the slice of bread is 125 kcal, which is the same as 125,000 calories. If all of this energy were converted to heat and absorbed by the person, the heat gained by the person would be:

Heat gained = energy in food = 125,000 calories

Assuming the specific heat of the person is 1.00 kcal/kg⋅°C, we can use the formula for specific heat:

Heat gained = (mass of person) x (specific heat) x (change in temperature)

We can rearrange this formula to solve for the change in temperature:

Change in temperature = Heat gained / [(mass of person) x (specific heat)]

Substituting the values given:

Change in temperature = 125,000 cal / [(65.0 kg) x (1.00 kcal/kg⋅°C)]

Change in temperature = 1923.08 °C

Therefore, the temperature of the person would increase by 1.92°C if all the energy in the bread were converted to heat. The best choice is (C).

A Slice of Bread Contains About 125 Kcal