Question

Question #21940

Answer 1

`-63.3` KJ (3sf) (Energy Lost)

Explanation:

So the equation for energy released in water is `Q = mcDeltaT`

Where Q is the amount of energy released, m is the mass of water, c is the specific heat capacity and `DeltaT` is the change in temperature.

So in your case:
`m = 710g`
`c = 4.18`
`DeltaT = 4 - 25 = -21`

Ensure the units are consistent with the units of the specific heat capacity. In this case this is the case as we are using grams.

Substitute the values in the equation.

`Q = mcDeltaT`
`Q = (710g)(4.18)(-21)`
`-63 300` J (3sf)
Or
`-63.3` KJ (3sf)

The negative energy indicates energy is lost.