In this lesson, you will investigate what happens to fossil fuels, such as hydrocarbons, when they burn. This process of burning is called combustion. To better understand the combustion of fossil fuels, you will access two online resources. Please answer the questions below based on your reading. Be prepared to discuss your answers in class.
- What do we mean that a hydrocarbon can go through combustion? What are we really doing to the hydrocarbon?
- Why do you think hydrocarbons make good fuels?
- Write the chemical reaction for the combustion of methane on the student sheet.
- How does the combustion of methane compare to the combustion of other hydrocarbon fossil fuels, like coal and oil?
Now go to Energy of Combustion. As you read, consider these questions. You can write your answers on your student sheet.
- What is the general chemical formula for the combustion of fossil fuels, or any hydrocarbons?
- Approximately, what percentage of the world’s energy needs is fulfilled by the combustion of fossil fuels?
- Combustion produces energy. Where does all this energy come from?
- Based on the diagram for the energy used and produced in the combustion of methane, fill in the chart on the student sheet.
- Based on your calculations, is energy needed or produced to combust methane? How do you know this based on your calculation?
- What does the term “endothermic” mean?
- In the steps on the chart, which ones are endothermic?
- What does the term “exothermic” mean?
- In the steps on the chart, which ones are exothermic?
- Overall, is the combustion of methane endothermic or exothermic?
Different hydrocarbons produce different amounts of energy when combusted, or burned. As we know from our calculations, the combustion of methane produces 802 kJ of energy. How much energy is produced from the combustion of ethane? Use the bond energy chart found on the top of the online resource, Energy from Fossil Fuels.
- What is the correct chemical reaction for the combustion of ethane?
- Determine the bond energies in each step of the combustion of ethane. Use the chart on the student sheet to do this.
- What is the total combustion energy for ethane?
- Is energy needed for this reaction or is it produced?
This esheet is a part of the Chemistry of Petroleum 2: What Happens to Hydrocarbons When They Burn? lesson.