Comparing Fossil Fuel and Biofuel Combustion

1. Comparing Fossil Fuel and Biofuel Combustion

2. Short Introduction Methane: • Anon-renewable fossil fuel gas pumped from deep below the Earth’s surface from both coal and oil deposits. • A major component of biogas - a renewable fuel that is produced from decaying plant and animal manure. Ethanol: • Renewable liquid biofuel produced from several different types of plant material. Octane: • A non-renewable liquid fossil fuel which is the major component of gasolinerefined from crude oil.

3. A Quick Review • Carbon-based fuels such as wood, coal, and gasoline supply energy. • These fuels release exothermic energy during a combustion chemical reaction. • The energy has been stored within the bonds of the molecules. • The energy is released because the chemical bond energy of the products are less than the chemical bond energy of the reactants. • The products of most combustion reactions include water and carbon dioxide

4. Bond Energy between two atoms Use the information in Table 1 to determine the energy in the bonds of each of the different molecules. TABLE 1: BOND ENERGY VALUES

5. Calculating the Total Bond Energy of a molecule. TABLE 1: BOND ENERGY VALUES Methane: CH4

6. Part B - Calculating the Energy Released During Combustion Reactions Use the information in Table 1 to determine the energy in the bonds of each of the different reactant molecules. TABLE 1: BOND ENERGY VALUES

7. PART 2: Calculating release energy • CH4 + O2→ CO2 + H2O

8. Part B - Calculating the Energy Released During METHANE Combustion CH4 + 2O2 → CO2 + 2H2O Energy released = (total bond energy of products) - (total bond energy of all reactants) REACTANTS Total Bond Energy in reactants = 2652.6 kJ/mole PRODUCTS Total Bond Energy in products = 3464.0 kJ/mole