# Entropy change at constant pressure and volume

1) Find the standard enthalpy of cyanamide (CH3N2 (s) ) from its heat of combustion to CO2 and H2O of -741.40kJ/mol.

2) Calculate delta S if the temperature of 2.50mol of an ideal gas with Cv = 5/2R is increased from 160K to 675k under conditions of

a. constant pressure

b. constant volume

https://brainmass.com/chemistry/energetics-and-thermodynamics/entropy-change-constant-pressure-volume-599218

#### Solution Summary

The enthalpy of formation of cyanamide is calculated from combustion data. The entropy change at constant pressure and volume for an ideal gas is calculated.

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