1. What is the change in enthalpy (∆H) for the contents of the cylinder? (kJ)

2. How much work is performed by the gas? (kJ) (Hint: The answer is a negative number.)

3. What is the change in internal energy (∆U) for the gas in the cylinder? (kJ)

 

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Description One mole of octane (C8H18) fuels an internal combustion engine. When the octane burns in a cylinder the piston moves upward, as shown below. (Assume that air is an ideal gas and is 80% N2 and 20% O2.) Note that ALL of the O2 is used in the reaction. 5.0 bar C8H18 + air T=25C insulated 5.0 bar CO,+ H,O T=? insulated Instructions Answer the following questions using the data below. Assume that the heat capacities are constant over this temperature range. Be sure to use the correct sign for questions 4 and 5. gas kJ/mol AfH J/mol.K C8H18(9) -208.8 75.6 CO2 -393.5 47.8 H2O(g) -241.8 40.3 N2 0 31.9 Description One mole of octane (C8H18) fuels an internal combustion engine. When the octane burns in a cylinder the piston moves upward, as shown below. (Assume that air is an ideal gas and is 80% N2 and 20% O2.) Note that ALL of the O2 is used in the reaction. 5.0 bar C8H18 + air T=25C insulated 5.0 bar CO,+ H,O T=? insulated Instructions Answer the following questions using the data below. Assume that the heat capacities are constant over this temperature range. Be sure to use the correct sign for questions 4 and 5. gas kJ/mol AfH J/mol.K C8H18(9) -208.8 75.6 CO2 -393.5 47.8 H2O(g) -241.8 40.3 N2 0 31.9

Answer rating: 100% (QA)

Solution Given data Heat of combustion of C8H18 2088 kJmol Heat of formation of CO2 3935 kJmol Heat ... View the full answer