Question

The formula shown below is used to calculate the energy released when a specific quantity of fuel is burned. Calculate the energy released by a burning sample of fuel if the temperature of 100g of water was raised by 20 °C. (Specific heat capacity of water = 4200J/kg °C)

Answer 1

Answer: 8400 J

Explanation:

The formula referenced in the question is:

$Q=m. c. \Delta T$  

Where:

$Q$  is the thermal energy

$m=100g \frac{1 kg}{1000 g}=0.1 kg$ is the mass  of the water sample

$c=4200 \frac{J}{kg\°C}$  is the specific heat capacity of  water

$\Delta T=20\°C$  is the variation in temperature

Solving:

$Q=(0.1 kg)(4200 \frac{J}{kg\°C})(20\°C)$  

$Q=8400 J$  This is the thermal energy released