The energy density of a fuel is the amount of useful energy - GED Practice Questions
Question
The energy density of a fuel is the amount of useful energy stored in a specific amount of that fuel. The energy density, measured in mega joules per kilogram (MJ/kg), is related to the chemical composition of the fuel. The chemical composition and energy density of four fuels are shown in the table.
Ethane, which has a chemical composition of CH is also a fuel.
What is the predicted energy density of ethane?
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Answers
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Explanation
The correct answer is: 52 MJ/kg
Analyzing the trend in the table, we see that as the ratio of hydrogen to carbon increases, the energy density also increases. Methane (CH₄) has the highest H:C ratio and the highest energy density. Ethane (C₂H₆) has a H:C ratio of 3:1, which falls between methane (4:1) and propane (2.67:1). Therefore, ethane's energy density should be between methane's 50 MJ/kg and propane's 47 MJ/kg, making 52 MJ/kg the most logical prediction.
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