3. Fossil fuels (petroleum, natural gas, and coal) are excellent fuels composed

Question

3. Fossil fuels (petroleum, natural gas, and coal) are excellent fuels composed primarily of hydrocarbons, which when burned in an adequate supply of air are oxidized, forming carbon dioxide and water. Chemical bonds are broken and new bonds are formed, and as a result, energy is released as heat. Calculate the following in the spaces provided using the table below. Show all work.

6760

Write a balanced chemical equation that includes a quantity of thermal energy for the complete combustion of the following alkanes:

Propane

Butane

Octane

Decane

Hydrocarbon Heat of Combustion (kJ/g) Molar Heat of Combustion (kJ/mol) Methane 55.6 890 Ethane 52 1560 Propane 50.0 2260 Butane 49.3 2859 Pentane 48.8 3510 Hexane 48.2 4151 Hepne 48.2 4817 Octane 47.8 5450 Decane 47.2

6760

Explanation / Answer

Hi balancing chemical equation is a trial and error method work, please be familiar or you may take help from online resources or any software for this purpose. Remember always first balance carbons only otherwise it will become more hardwork and tedious.

1. Propane Combustion equation:

C3H8 (g) + 5O2 (g) 3CO2 + 4H2O  (g) H = -2260 kJ/mol

2. Butane Combustion equation:

C4H10 (g) + O2 (g) 4CO2 (g) + 5H2O (g)   H = -2859 kJ/mol

3. Octane Combustion equation:

2 C8H18 (g) + 25 O2 (g) 16 CO2 (g) +18 H2O (g) H = -5450 kJ/mol

4. Decane Combustion equation:

2 C10H22 (g) + 31 O2 (g) 20 CO2 (g) + 22 H2O (g)         H = -6760 kJ/mol

NOTE: All H values have a negative sign before the energy value, it represents an exothermic reaction (Thermal enrgy released).

Thank You So Much! Please Rate this answer as you wish.

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