Question

The enthalpy of combustion of gasoline (C₈H₁₈) is 5471 kJ mol⁻¹. How much heat will be produced by burning 1 gallon of gasoline at 25°C? (Density of gasoline = 0.703 g/mL; 1gallon = 3.78 L) Show your work clearly.

Answer 1

To find the heat produced by burning 1 gallon of gasoline at 25°C, convert the volume of gasoline into moles and multiply by the enthalpy of combustion.

Step-by-step explanation:

The enthalpy of combustion of gasoline is 5471 kJ mol⁻¹. To find how much heat will be produced by burning 1 gallon of gasoline at 25°C, we need to calculate the number of moles of gasoline in 1 gallon. First, convert the volume of 1 gallon into liters by multiplying by the conversion factor 3.78 liters/gallon. Next, calculate the mass of gasoline in grams by multiplying the density of gasoline (0.703 g/mL) by the volume in mL. Then, convert the mass of gasoline into moles by dividing by the molar mass of gasoline (C₈H₁₈). Finally, multiply the number of moles by the enthalpy of combustion to find the heat produced.

Step 1: 1 gallon x 3.78 liters/gallon = 3.78 liters

Step 2: 3.78 liters x 1000 mL/liter = 3780 mL

Step 3: 3780 mL x 0.703 g/mL = 2658.54 g

Step 4: 2658.54 g / 114.22 g/mol = 23.25 mol

Step 5: 23.25 mol x 5471 kJ/mol = 127,135.75 kJ