Question

Using the table for standard enthalpy of formation, solve 2 H2S(g) + 3 O2(g) --> 2 H2O(l) + 2 SO2(g)

Answer 1

Step-by-step explanation:

Binding energy, or enthalpy of binding, is the energy absorbed in the breaking of one mole of bond, in the gaseous state, between atoms at 25 oC and 1 atm. This definition may also involve the energy present in the formation of the same bond between the same (separate) atoms, but it will have a different sign.

Calculation of binding energy

By calculating the binding energy present in a chemical reaction, we can determine whether that reaction is endothermic or exothermic. To do this, just use the expression below:

ΔH = Σr - Σp

ΔH = enthalpy change;

Σr = sum of the energies needed to break each bond in the reactant;

Σp = sum of energies required to form each bond in the product.

Energies needed to break each bond in the reactant:

H2S:

2 S-H Energy = 347 * 2 = 694 kJ/mol

O2:

1 O=O Energy = 498 kJ/mol

Σr = 694 + 498 = 1,192 kJ/mol.

Energies required to form each bond in the product:

H2O:

2 O-H Energy = 467*2 = 934 kJ/mol

SO2:

2 S=O Energy = 523*2 = 1,046 kJ/mol

Σp = 934 + 1,046 = 1,980 kJ/mol

ΔH = 1,192 - 1,980 = -788 kJ/mol

Answer: -788 kJ/mol