Determine the vapor pressue of pentane on a cold autumn morning when the temperature is 3.10 °C.

Question

Portable lanterns and stoves used for camping and backpacking often use a mixture of C₅ and C₆ hydrocarbons known as "white gas." White gas is easy to transport but stoves that burn white gas are harder to light in the cold. The figure below shows the structure of pentane, a typical C₅ alkane, its normal boiling point is 36.0 ^oC and its heat of vaporization is 27.6 kJ/mol.

Answer 1

Use Clausius Clapeyron

ln(P1/P2) = -ΔHvap/R (1/T1 - 1/T2)

P1 = 1 atm

T1 = 36+273 = 309K

P2 = ?

T2 = 3.1+273 = 276.1K

DeltaH = 27.6 kJ/mol

R = 8.314 J/mol K

plug in the values and solve for P2