# Problem: The standard enthalpies of formation of gaseous propyne (C3H4), propylene (C3H6), and propane (C3H8) are +185.4, +20.4, and -103.8 kJ/mol, respectively.Calculate the heat evolved on combustion of 6 kg of each substance.

###### FREE Expert Solution

We are asked to calculate the heat evolved on combustion of 6 kg of each substance.

C3H4(g) + 4 O2(g) → 3 CO2(g) + 2 H2O(g).

ΔH˚rxn = –1849.5 kJ/mol

Calculate for 6 kg C3H4

Molar mass C3H4 =40.07 g/mol

= -2.77 x 105 kJ

The heat evolved for 6 kg of C3H4 is -2.77 x 105 kJ

C3H6(g) + 9/2 O2(g) → 3 CO2(g) + 3 H2O(g).

98% (41 ratings)
###### Problem Details

The standard enthalpies of formation of gaseous propyne (C3H4), propylene (C3H6), and propane (C3H8) are +185.4, +20.4, and -103.8 kJ/mol, respectively.

Calculate the heat evolved on combustion of 6 kg of each substance.

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Enthalpy of Formation concept. You can view video lessons to learn Enthalpy of Formation. Or if you need more Enthalpy of Formation practice, you can also practice Enthalpy of Formation practice problems.