Question

Question #fdbe9

Answer 1

You are correct! The mass of aluminium would be 629.8 g.

Explanation:

The formula for the amount of heat transferred is

`q = nΔ_"fus"H`

where

• `q` is the amount of heat transferred
• `n` is the number of moles of substance
• `Δ_"fus"H` is the molar enthalpy of fusion of the substance

`q = "250.0 kJ"`

`Δ_"fus"H = "10.71 kJ·mol"^"-1"`

∴ `n = q/(Δ_"fus"H) = (250.0 color(red)(cancel(color(black)("kJ"))))/(10.71 color(red)(cancel(color(black)("kJ")))"·mol"^"-1") = "23.343 mol"`

Now, we must convert moles of `"Al"` to grams of `"Al"`.

`"Mass of Al" = 23.343 color(red)(cancel(color(black)("mol Al"))) × "26.982 g Al"/(1 color(red)(cancel(color(black)("mol Al")))) = "629.8 g Al"`