Question

Question #05480

Answer 1

You're dealing with a phase change, so you need to determine how much heat you need to supply to the ice to get to go from solid at `0^@"C"` to liquid at `0^@"C"`.

The equation you'll use looks like this

`q = m * DeltaH_"fus"`, where

`q` - the heat you need to suplly to the ice;
`m` - the mass of the ice;
`DeltaH_"fus"` - the latent heat of fusion, or enthalpy of fusion, which is the change in enthalpy you get when you heat a gram of a substance to change it from solid state to liquid state.

The enthalpy of fusion for ice has a value of 334 J/g. This means that, if you have 1 gram of ice at `0^@"C"`, you need to supply it with 334 J of heat in order to get it to liquid at `0^@"C"`.

Since you've got more than one gram of ice, you'll of course need more than 334 J of heat.

`q = 35.0cancel("g") * 334"J"/cancel("g") = "11690 J"`

Expressed in kJ and rounded to three sig figs, the answer will be

`11690cancel("J") * "1 kJ"/(1000cancel("J")) = color(green)("+11.7 kJ")`

The + sign symbolizes that the heat is provided to the ice.