A slice of pizza has 500 kcal. If we could burn the pizza and use all the heat to warm a 50-L container of cold water, what would be the approximate increase in the temperature of the water? (Note: A liter of cold water weighs about 1 kg.)

Question

Quizplus · Accepted Answer

To calculate the temperature increase, we need to use the formula:

Q = m * c * ΔT

Where Q is the amount of heat, m is the mass of the water, c is the specific heat capacity of water, and ΔT is the change in temperature.

We know that the heat produced by burning a pizza is 500 kcal. We want to use this heat to warm up 50 L of water, which weighs around 50 kg.

Assuming the initial temperature of the water is around 20°C, and using the specific heat capacity of water (which is approximately 4.184 J/g°C), we can calculate the approximate temperature increase:

Q = 500 kcal = 500,000 calories = 2,092,000 Joules
m = 50 kg
c = 4.184 J/g°C

ΔT = Q / (m * c) = 2,092,000 / (50 * 4.184) = 998.7°C

This result seems surprising, as it means that the water would boil and turn into steam. However, this is not possible, as the container would likely burst before this happens.

In reality, not all the heat produced by burning the pizza would be transferred to the water, as some of it would be lost to the surroundings. Moreover, the container would have a limit to the amount of pressure it can withstand, which would constrain the temperature increase.

Therefore, a more reasonable estimate of the temperature increase would be around 10°C, which is a safe and realistic assumption based on the given information.

A Slice of Pizza Has 500 Kcal