# 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:?

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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:

Hfo

(H2O(g))= -241.82 kJ/mol

Hfo

(CO2(g))= -393.5 kJ/mol

Hfo

(C2H2(g))=226.77 kJ/mol

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:

Hfo

(H2O(g))= -241.82 kJ/mol

Hfo

(CO2(g))= -393.5 kJ/mol

Hfo

(C2H2(g))=226.77 kJ/mol

##### 1 Answer

#### Explanation:

Hess' Law states that the overall enthalpy change of a reaction is independent of the route taken.

Thermodynamics is concerned with initial and final states and the law is a consequence of the conservation of energy.

You can solve this problem by constructing a Hess Cycle.

Write down the reaction you are interested in. Below this write down the elements from which the reactants and products are made.

Then complete the cycle as shown:

Notice I have multiplied the

In energy terms the

So we can write: