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Here are some suggested answers for the questions found on the Understanding Crude Oil student sheet.
- Energy from the sun is used by plants to combine carbon, hydrogen, and oxygen into high-energy molecules. What is this process called? What is an example of a high-energy molecule made by plants through this process?
It is called photosynthesis. One example is sugars.
- What happens to most organisms when they die?
They begin to decay and decompose.
- Instead of decaying and decomposing like most organisms when they die, some organisms die in certain conditions appropriate for making fossil fuels. What are these conditions described in the video?
The organisms fell to the bottom of the ocean or lake floor, were quickly buried, were not exposed to oxygen, and were covered with sediment.
- What is kerogen?
It is a collection of the organic matter from the decayed organisms that has been squeezed together over time under high temperature and pressure.
- Why do you think kerogen is a high-energy substance?
It is a collection of hydrocarbons, which have energy stored in their hydrogen-carbon bonds. The process of converting the energy from the sun into these bonds is photosynthesis.
- Over time, more and more sediment covered the kerogen, increasing the temperature and pressure above it. As temperature and pressure rose, what process broke or cracked the long organic molecules into smaller hydrocarbons?
The process is called catagenesis.
- Under what conditions would natural gas be produced instead of petroleum?
Higher pressures and temperatures produce small hydrocarbons through catagenesis.
- What is the difference between kerogen and petroleum?
Kerogen is composed of long chains of hydrocarbons. After the process of catagenesis, the collection of smaller hydrocarbons chains is known as petroleum.
- Why does petroleum travel up through the rock against gravity?
Petroleum is lighter than the rock and water around it, so it travels up.
- How do petroleum deposits form under the surface?
As the petroleum rises, it may get trapped under some non-porous rock.
- How is the stored energy within petroleum’s hydrocarbons released?
Combustion reactions or burning with oxygen release the stored energy.
- Why do you think it is important to understand how oil is refined?
Answers may vary. Encourage students to explain their answers.
- What role does energy play in our everyday lives? What is its significance?
Energy seems to be an essential part of our modern, industrial life. It allows us to cook our food in the convenience of our own homes, turn on the lights, drive our cars, and work on computers. What would our lives be like without it?
This teacher sheet is a part of the Chemistry of Petroleum 3: Distillation of Hydrocarbons