Lab One – Carbon Dioxide and Your Car. The purpose of this lab is to have you be aware of the amount of CO2 that is emitted from an average car drive to your cabin up north. The reason we focus on Carbon Dioxide is that the emission of this gas changes the climate, according to the majority of scientists studying the changes in our climate. Natural emission of CO2 is much greater than that produced by humans.

The natural carbon cycle in nature absorbs much of the CO2 produced. However, vegetation and oceans only absorb about 40% of the CO2 produced. In addition, human activities such as livestock production add significantly to the production of both CO2 an methane gas. So, what are some of the numbers we can become aware of?

• Carbon Dioxide released by consumption of vegetation by animals and microbes – 220 gigatonnes of CO2/year.
• Carbon Dioxide released by respiration of vegetation – another 220 gigatonnes of CO2/year.
• Carbon Dioxide released by the oceans – 332 gigatonnes of CO2/year.
• Carbon Dioxide released by human activities – 29 gigatonnes of CO2/year.

Offset- The absorption of CO2 by plants (450 gigatonnes/year) and the oceans (338 gigatonnes/year) for a total of 788 gigatonnes/year. What this tells us is that plants produce about 440 gigatonnes and absorbs about 450 gigatonnes. The oceans produce 332 gigatonnes and absorb 338 gigatonnes. Considering variations from year to year, this creates a rough balance.

Adding 17.5 gigatonnes/year through human activities is the real concern because this is NOT absorbed by natural processes and we have to consider the cumulative effect. We hear a lot about carbon dioxide emissions from everyday activities. Where does it actually come from? It all starts with combustion. Combustion is the chemical reaction producing heat and light. It often involves a fuel and oxygen although combustion can occur with other compounds as well. For example, hydrogen will burn in chlorine to produce hydrogen chloride with heat and light being given off. However, for many everyday situations, combustion involves a carbon based compound and oxygen (gasoline and oxygen for example).

Oxygen combines with carbon in the fuel to generate Carbon Dioxide (CO2).

1. In general, each gallon of gas weighing 6.25 pounds gives rise to about 19.3 pounds of Carbon Dioxide.

2. How is this possible, you ask? No laws of physics are being broken. Gasoline is a mixture of materials, but octane is important in combustion, and it has 8 Carbons and 18 Hydrogens)

3. 1 molecule of octane will produce 8 molecules of CO2, and 9 molecules of water. It produces 8 molecules of CO2 because each of the eight carbon atoms will react with oxygen. So the weight of the carbon and the weight of the oxygen are now added together. It also explains why you may see water vapor asociated with engine exhaust.

If we consider the atomic weight of carbon (12), hydrogen (1) and oxygen (16), we find the following: Carbon Dioxide = 12 amu and oxygen (16×2) = 32.

So 12 + 32 = 44 atomic mass units. We must multiply (44 x 8 = 352) because each octane gives rise to 8 molecules of carbon dioxide. Octane has a weight of 114 (C (8 x 12 ) + H (18 x 1) or 96 + 18 = 114).

6.25 pounds of gasoline x 352/114 = 6.25 x 3.09 = 19.3 pounds of Carbon Dioxide per gallon of gas.

So burning one gallon of gasoline will produce 19.3 pounds of CO2.

Keep in mind that combustion efficiency will cause this number to vary, but it is a very useful number for obtaining a general idea regarding the amount of CO2 produced from an activity that most everyone is involved in either as a driver or a passenger. We humans drive a lot of cars, and airplanes are even worse.

YOU MUST COMPLETE THE FOLLOWING: USE THE INFORMATION ABOVE TO ANSWER THE FOLLOWING QUESTIONS.

LAB Assignment: So now I would like you to determine how much Carbon Dioxide is produced if you take a round trip drive to your cabin up north.

We will assume that the round trip distance is 150 miles and your mileage is 30 miles/gallon.

Answer these three questions and submit them to the drop box for lab one.

1. Determin the amount of CO2 produced in pounds for one trip and back from the cabin.

2. Then, calculate the amount of CO2 produced from 10 summer trips to the cabin.

3. What does this say about the amount of CO2 produced by the average person in a year?

put the answers to these questions in the drop box for lab one. Put them in a word document.

I think we all better car pool more…..