Question #30924

1 Answer
Oct 29, 2016

Answer:

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)|)))#