13. The chemical composition and energy density of four fuels are shown in the table. Ethane, which has a chemical composition of C2H6, is also a fuel. What is the predicted energy density of ethane?
Answer: C
The predicted energy density of ethane is 52 MJ/kg.
The energy density of ethane, with its chemical composition of C2H6, is predicted to be 52 MJ/kg based on its chemical properties and comparison with other fuels.
A) 45 MJ/kg
This option is incorrect as it underestimates the energy density of ethane. Given the chemical composition of ethane, it possesses a higher energy release potential than what is suggested by this value.
B) 42 MJ/kg
This option is also incorrect. An energy density of 42 MJ/kg fails to account for the chemical characteristics of ethane, which indicate a higher energy output per kilogram than this figure.
C) 52 MJ/kg
This option is correct. Ethane's chemical structure allows it to have an energy density of 52 MJ/kg, which aligns with the expectations for hydrocarbons of similar composition and structure.
D) 48 MJ/kg
This option is incorrect as it represents a value that is too low for ethane. While it is closer to the correct prediction than some other options, it still does not capture the full energy potential of ethane based on its molecular makeup.
Conclusion
The correct answer is 52 MJ/kg, as it accurately reflects the energy density of ethane based on its chemical composition. Other options fail to recognize the potential energy stored in ethane, leading to underestimations of its energy density in comparison to its actual value.