Question

Question #30924

Answer 1

Here's what I got.

Explanation:

In order to be able to answer this question, you need to know the enthalpy of fusion, `DeltaH_"fus"`, of water

`DeltaH_"fus" = "333.55 J g"^(-1)`

https://en.wikipedia.org/wiki/Enthalpy_of_fusion

Now, the enthalpy of fusion is a measure of how much heat is needed to melt `"1 g"` of ice at its melting point to liquid water at its melting point.

In other words, the enthalpy of fusion tells you how much heat is needed to make `"1 g"` of ice undergo a solid `->` liquid phase change at `0^@"C"`.

In order to calculate the heat needed to melt `"51.0 g"` of ice at its melting point, use the enthalpy of fusion as a conversion factor

`51.0 color(red)(cancel(color(black)("g"))) * "333.55 J"/(1color(red)(cancel(color(black)("g")))) = "17011 J"`

Rounded to three sig figs and expressed in kilojoules, the answer will be

`color(green)(bar(ul(|color(white)(a/a)color(black)("heat needed " = " 1.70 kJ")color(white)(a/a)|)))`