In: Chemistry
Use the data provided to calculate benzaldehyde’s heat of
vaporization.
Vapor Pressure (torr) | Temperature (K) |
32.5 | 363.0 |
934 | 458.0 |
Answer =
Heat of vaporisation of benzaldehyde = 48.98 kj/mol
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The clausius-clapyeron is employed to calculte the heat of vapourisation of given liquid benzaldehyde.
If the vapor pressures are known at respective temperatures then the clausius-clapyeron equation detrmines the enthalpy of vaporization of the substance.
The clausius-clapyeron Equation,
P1 = 32,5 torr at T1 = 363.0 K
P2= 934 torr at T2= 458.0 K
Enthalpy of vaporisation , = ?
Gas constant, R = 8.3145 J mol-1 K-1
The pressure units given in Torr can be used as it is without botheration of converting to atm or pa. Since the mupltiplication facto is common for both numerator and denominator it cancels out.
= 48,982.45 j/mol
= 48.98 kj/mol [ All units balanced . Fulfilled dimension analysis]