Question

Question #d9ce7

Answer 1

`T_2 = "291 K" = 17.8^@ "C"`

Explanation:

Use the ‘Clausius - Clapeyron Equation’ with

`VP_1 = "760 mm Hg"` @ `T_1 = "373 K"`

`VP_2 = "19 mm Hg"` @ `T_2 = ?`

`R = "8.314 J/mol"cdot"K" = "0.008314 kJ/mol"cdot"K"`

`∆H_(vap) = "40.67 kJ/mol"`.

And so:

`ln((VP_2)/(VP_1)) = ((∆H_(vap))/R)[1/T_1 – 1/T_2]`

`ln(19/760) = (40.67/0.008314)[1/373 – 1/(T_2)]`

`ln(0.025) = (4865)[0.0027 – 1/T_2] = 13.04 – 4865/T_2`

`=> -3.69 = 13.04 - 4865/T_2`

Rearrange to solve for `T_2`.

`T_2 = [(4865)/(13.04 + 3.69)]"K"`

`= (4865/16.73)` `"K"` `=` `"291 K"`

Or in `""^@ "C"`,

`T_2 = (291 - 273)""^@"C"`

`= 17.8^@ "C"`