Trouton\'s rule states that the molar enthalpy of vaporization of a liquid that does not have strong molecular interactions such as hydrogen bonding or ion-ion attractions is given by ΔHvap = (85 J x K^-1 x mol^-1)Tb where Tb is the normal boiling point of the liquid in kelvins.
a) Apply Trouton\'s rule to estimate the value of ΔHvap for these compounds.
Chloromethane, Water, and hydrogen sulfide - all in kJ/mol.

b) Compared to the accepted ΔHvap values (given in the \"Hint\") what is the percentage error in each case?

Respuesta :

Question a:

Calculate ΔHvap for Chloromethane, Water, and hydrogen sulfide - all in kJ/mo, using Trouton's rule: ΔHvap = (85 J x K^-1 x mol^-1)Tb where Tb is the normal boiling point of the liquid in kelvins.

We need Tb for
Chloromethane, Water, and hydrogen sulfide

Chloromethane: -23.8°C = 249.3 K
Water: 100°C = 373.1K
Hydrogen sulfide: -60°C = 213.1K


ΔHvap = (85 J x K^-1 x mol^-1)Tb

Chloromethane: 85 (J/mol*K) *249.3 K= 21,190.5 J/mol

Water:
85 (J/mol*K) *373.1K= 31,713.5 J/mol

Hydrogen sulfice:
85 (J/mol*K) *213.1 K= 18,113.5 J/mol

Question b) Compared to the accepted ΔHvap values (given in the \"Hint\") what is the percentage error in each case?

You didn't include the "HInt". Then I am going to explain how to find the error:

For each product, take the value calculated with the formula, subtract if from the value shown in the Hint, then divide the difference by the value shown in the HInt and mutiply times 100. The result is the percentage of error.

Be very careful of using same units. The values calculated have units J/mol. So if the units of the values of the HInt are not the same you have to make the conversion. If you need to convert grams to moles,  use the molar mass of each compound.