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First Law of Thermodynamics

Fuel Economy and Second Law of Thermodynamics for Otto-cycle of a certain car

The Otto-cycle of a certain car has a compression ratio r=8.5. The fuel economy rating of this car is 25 miles per gallon at 105km/h. Gasoline has a heat of combustion of 4.60x10^7J/kg, and its density is 740kg/m^3. a. At 105km/h, what is the rate of gasoline consumption in L/h? b. What is the theoretical efficiency of

Laws of thermodynamics : Changes in internal energy.

The specific heat of air at constant volume is 0.175 cal/gm deg Celsius a) By how much does the internal energy of 5 gm of air change as it is heated from 20 deg to 400 deg? (b) Suppose that 5gm of air is adiabatically compressed so as to raise its temperature from 20deg to 400 deg. How much work must be done on the air to