Electricity in Your Home: Activity 2 :Key

One molecule of methane plus two molecules of oxygen will
burn to produce two molecules of water, one molecule of carbon dioxide, and heat.



Transparency Master

Molecular equation

Word Equation

Mass equation


Transparency Master
  1. Using the graph provided, determine the mass (in kilograms) of carbon dioxide that is produced in order to generate

    1. 20kWh of electrical energy.
      Answer: approximately 26kg CO2

    2. 40kWh of electrical energy.
      Answer: approximately 52kg CO2

    3. 100kWh of electrical energy.
      Answer: approximately 77kg CO2

  2. A single 1500 W electrical baseboard heater will use about 216kWh in one month of operation, having a 20% duty cycle (meaning that it is "on" 20% of the time). How much CO2 is produced?
    Answer: approximately 175kg CO2

  3. Acquire an electrical utility bill. Examine the bill and determine the amount of electrical energy used. What mass of CO2 is produced to generate this amount of electrical energy?
    Answer: various quantities will be used depending upon the billing season. Typically 2000kWh of electricity will generate about 1600 kg of carbon dioxide.

*Note: Not everyone is willing to share their electricity consumption information with others. It may be prudent to have a couple of "anonymous" billing samples available for student use.

* Footnote: Fossil fuels are a complex blend of hundreds of kinds of hydrocarbon molecules. The molecule in this example is one of the most abundant in the fuel being described, and as such, represents a good approximation of the entire combustion process

This activity assumes that all the electricity used is from a single type of fuel. This is generally not the case. The actual amount of carbon dioxide produced varies from region to region as will be shown later.

YES I Can! Science