Question

Almonds and almond extracts are common ingredients in baked goods. Almonds contain the compound benzaldehyde, shown below, which accounts for the odor of the nut. Benzaldehyde is also responsible for the aroma of cherries. Use the data provided to calculate benzaldehyde’s heat of vaporization. answer in kj/mol

Vapor Pressure (torr) Temperature (K)

(K)

56.8 376.0

602 443.0

Answer 1

We solve by the following formula:

H=(R*T₁*T₂*lnp₁/p₂)/(T₂-T₁),

R - Universal gas constant: 8.314 j/mol*K

T₂ and T₁ - temperature, K

p₁ and p₂ - pascal pressure

p₁=7572,711Pa

p₂=80 260.1Pa

 

H=((8.314j/mol*K*376K*443K*(ln80,26 *10³Pa^/7,57*10³Pa))/(443K-376K)=8.314*376*443*ln10.60/67=

8.314*376*443*2.36/67=48 779.66 j/mol =48,8 kj/mol