Question

The heat of fusion for water is 80. cal/g. How many calories of heat are needed to melt a 35 g ice cube that has a temperature of 0 C?

Answer 1

You need `2.8 × 10^3 color(white)(l)"cal"` to melt the ice cube.

Explanation:

The formula for the heat required to melt a solid is

`color(blue)(|bar(ul(color(white)(a/a) q= mΔ_"fus"H^°color(white)(a/a)|)))" "`

where

`q = "the amount of heat"`
`m = "the mass of the solid"`
`Δ_"fus"H^° = "the enthalpy of fusion"`

`m = "35 g"`
`Δ_"fus"H^° = "80. cal·g"^"-1""`

∴ `q = 35 color(red)(cancel(color(black)("g"))) × "80. cal"·color(red)(cancel(color(black)("g"^"-1"))) = 2bar8 00color(white)(l) "cal" = 2.8 × 10^3 color(white)(l)"cal"`