Question

How many calories are required to raise the temperature of 105 g of water from 30.0°c to 70.0°c?

Answer 1

Answer: 4200 calories

Let's start by explaining that 1 Calorie (
`1 cal`) is defined as a unit of thermal energy that is equivalent to the amount of heat (
`Q`) needed to raise the temperature of 1 gram
`1g` of water by 1 degree Celsius
`1\°C`.

The formula to calculate it is:

`Q=m. c. \Delta T` (1)

Where:

`m` is the mass

`c` is the specific heat of the element. In the case of water
`c=1cal/g`

`\Delta T` is the variation in temperature, which in this case is
`\Delta T=70\°C-30\°C=40\°C`

Rewriting equation (1) with the known values:

`Q=(105g)(1 cal/g)(40\°C)`

`Q=4200 cal`