If 5,100 Joules of heat are released when a sample of water freezes,what is the mass of the water?

Mar 5, 2018

15.3 grams

Explanation:

When water freezes at 0 degrees C it loses potential energy to the surroundings, without changing its temperature. This is known as the Latent Heat of Fusion of water . I.e the energy change $x$ mass of water changes to $x$ mass of ice under constant temperature. The same story goes for when steam at 100 degrees C condenses back to water at constant temperature, this energy change is known as the Latent Heat of Vaporization of water.

This is given by the equation:

$Q = m L$ where Q is the energy released/ put in, m is the mass of the substance and L is the Latent heat of vaporization/fusion of the substance in question.

Now $Q = 5100 J$, $L = 334 J {g}^{-} 1$ and $m$ is our uknown.

$5100 = 334 \times m$
$m \approx 15.3$ grams