Question #27012

1 Answer
May 3, 2017

Answer:

#1.50 * 10^4"kJ"#

Explanation:

You need to know the value of water's enthalpy of fusion, #DeltaH_"fus"#

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

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

The enthalpy of fusion tells you the amount of heat needed to convert #"1 g"# of a substance from solid at its melting point to liquid at its melting point.

For water, you need #"333.55 J"# to convert #"1 g"# of water from solid at #0^@"C"#, i.e. from ice, to liquid at #0^@"C"#.

This implies that #"45.0 g"# of ice will require

#45.0 color(red)(cancel(color(black)("g"))) * "333.55 J"/(1color(red)(cancel(color(black)("g")))) = "15009.75 J"#

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

#color(darkgreen)(ul(color(black)("heat needed" = 1.50 * 10^4color(white)(.)"kJ")))#