Question

A 0.250 kg sample of water at room temperature (20.0°C) is placed in a microwave. After one minute the temperature of the water is 80.0°C. How many calories have been added to the water?

Answer 1

The heat added to the water when it was heated from 20.0°C to 80.0°C is 15000 calories.

Step-by-step explanation:

The student has asked how many calories have been added to a 0.250 kg sample of water when its temperature was raised from 20.0°C to 80.0°C using a microwave. The specific heat capacity of water is 1 cal/g°C, which is the amount of heat needed to raise the temperature of 1 gram of water by 1°C.

To calculate the heat added in calories, we use the formula:

Q = m × c × ΔT

where:
• Q is the heat added in calories
• m is the mass in grams
• c is the specific heat capacity (1 cal/g°C for water)
• ΔT is the change in temperature in degrees Celsius

First, convert the mass from kilograms to grams:

m = 0.250 kg × 1000 g/kg = 250 g

Then, calculate the change in temperature:

ΔT = 80.0°C - 20.0°C = 60.0°C

Now we can calculate the heat added:

Q = 250 g × 1 cal/g°C × 60.0°C = 15000 calories