Question

How many joules are required for heating 65 g of water from 12 °C to 76 °C?

Answer 1

`17000` joules

Explanation:

With knowledge of the specific heat capacity of a substance, its mass, and the temperature change, we can convert this to the energy required for this temperature change using:

`DeltaH=mCDeltaT`, where

`DeltaH=`change in enthalpy (J)

`m=` mass of substance being heated (g) i.e. water in this question

`C=` specific heat capacity (J/g°C)

`DeltaT=` change in temperature (°C)

We know mass`=65g` and `DeltaT=76°C-12°C=64°C`

The specific heat capacity of water is `4.18`J/g°C

Therefore, `DeltaH=65cancel(g)*(4.18J)/cancel(g°C)*64cancel(°C)`

`=17388.8J`

`=17000J` (2 significant figures)