Question

Question #3de10

Answer 1

`"29,900 J"`

Explanation:

In order to be able to answer this question, you need to know the value of the enthalpy of fusion, `DeltaH_"fus"`, of water, which you'll find listed as

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

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

Now, the enthalpy of fusion of a given substance tells you the amount of heat needed in order to convert `"1 g"` of said substance from solid at its melting point to liquid at its melting point.

In this case, you can say that in order to convert `"1 g"` of ice at its normal melting point of `0^@"C"` to `"1 g"` of liquid water at `0^@"C"`, you need to provide it with `"333.55 J"` of heat.

You can thus say that you will need

`89.5 color(red)(cancel(color(black)("g"))) * overbrace("333.55 J"/(1color(red)(cancel(color(black)("g")))))^(color(blue)(=DeltaH_"fus")) = color(darkgreen)(ul(color(black)("29,900 J")))`

in order to melt `"89.5 g"` of ice at its normal melting point.

The answer is rounded to three sig figs, the number of significant figures you have for the mass of ice.