Question

Calculate the standard heat of formation of propane, if its heat of combustion is 0-2220.2 KJ mol^-1 the heats of formation of CO_2(g) and H_2(g) O_(I) are -393.5 and -285.8 kJ mol^-1 respectively.

Answer 1

Standard heat of formation of propane, 

3C_(g) + 4H_2(g) → C₂H_8(g) ∆H_f° = ? 

Data given:

According to Hes&s law, equation 

Equation (1) is reversed. 

Equation (2) is x 3 

Equation (3) is x 4 

The add all the equations.

Standard enthalpy of formation of propane ∆H_f° = -103.5 K.J mol^-1