Question

Click the DeltaH is an Extensive Property button within the activity, and analyze the relationship between the two reactions that are displayed. The reaction that was on the screen when you started and its derivative demonstrate that the change in enthalpy for a reaction, ΔH, is an extensive property. Using this property, calculate the change in enthalpy for Reaction 2. Reaction 1: C3H8(g)+5O2(g)→3CO2(g)+4H2O(g), ΔH1=−2043 kJ Reaction 2: 6C3H8(g)+30O2(g)→18CO2(g)+24H2O(g), ΔH2=? Express your answer to four significant figures and include the appropriate units.

Answer 1

Answer:

∴ΔH₂ = - 12,258 KJ

Explanation:

Enthalpy:

Enthalpy is a property of a thermodynamic system. Enthalpy of a system is equal to the sum of internal energy of the system and presser times volume of the system.

    The heat absorbes or releases in a closed system is the change of enthalpy of the system.

Given reactions are:

Reaction 1: C₃H₈(g)+5O₂(g)→ 3CO₂(g)+4H₂O,                 ΔH₁= - 2043 KJ

Reaction 2: 6C₃H₈(g)+30 O₂(g)→ 18 CO₂(g)+24 H₂O,     ΔH₂=?

Take a look at reaction 1 and reaction 2, the only difference is that 1 molecule of C₃H₈ is combusted in reaction 1 and 6 molecules of C₃H₈  is  combusted in reaction 2.

We can think the reaction 2 as occurring 6 different container and each containers contains 1 molecule of C₃H₈. The enthalpy is an extensive property. Total enthapy of the 6 containers is = 6×(-2043 KJ)

                                                                            = - 12,258 KJ

∴ΔH₂ = - 12,258 KJ