Question

Acetylene is used in blow torches, and burns according to the following equation: 2 C2H2(g) + 5 O2(g) → 4 CO2(g) + 2 H2O(g). Use the following information to calculate the heat of reaction: H f o (H2O(g))= -241.82 kJ/mol H f o (CO2(g))= -393.5 kJ/mol H f o (C2H2(g))=226.77 kJ/mol

Answer 1

-2511.18KJ

Step-by-step explanation:

The heat of reaction is accessible from the heat of formation of reactants and products using the formula below:

ΔH = Σ ΔHf products - Σ ΔHf reactants

Now ,in the specific case of the reaction in the question, 2 moles of acetylene burned in 5 moles of oxygen to yield, 4 moles of carbon (iv) oxide and 2 moles of steam.

It should be noted that the heat of formation of elements is zero and are not taken into consideration when calculating the heat of formation of reaction.

Thus, in this case, the heat of formation of the 5 moles of oxygen is taken as zero.

The heat of reaction is calculated mathematically as follows :

ΔH = [ (4 moles of carbon(iv) oxide × -393.5) + ( 2 moles of water × -241.82)] - [ (2 moles of acetylene × 226.77) + ( 5 moles of oxygen × 0)]

-1574KJ - 483.64KJ - 453.54KJ = -2511.18KJ