Question

Question #8b4e9

Answer 1

The maximum mass of sodium that can be boiled is 114 g.

Explanation:

The amount of heat `q` required to vaporize a substance is given by the formula

`color(blue)(bar(ul(|color(white)(a/a) q =nΔ_"vap"H color(white)(a/a)|)))" "`

where

`n = "number of moles"`

`Δ_"vap"H = "enthalpy of vaporization"`

∴ `n = q/( Δ_"vap"H)`

For sodium, `Δ_"vap"H = "97.7 kJ/mol"`

`n = (486 color(red)(cancel(color(black)("kJ"))))/(97.7 color(red)(cancel(color(black)("kJ")))·"mol"^"-1") = "4.974 mol"`

`"Mass of Na" = 4.974 color(red)(cancel(color(black)("mol"))) × "22.99 g"/(1 color(red)(cancel(color(black)("mol")))) = "114 g"`