Question

The heat of combustion for n-heptane, C₇H₁₆, is 4817 kJ/mol. How much heat is released if 498 kg of this liquid burns completely?

A)1.45 × 10⁶ kJ
B)2.40 × 10⁶ kJ
C)4.81 × 10⁶ kJ
D)8.09 × 10⁶ kJ

Answer 1

By converting the mass of n-heptane to moles and then multiplying it by the heat of combustion per mole, we calculate the total heat released. However, the calculated value of 23.92 × 10⁶ kJ does not match any of the provided options, indicating a discrepancy in the answer choices.

Step-by-step explanation:

To determine how much heat is released by the combustion of 498 kg of n-heptane, C₇H₁₆, we use the heat of combustion provided, which is 4817 kJ/mol. First, we convert the mass of n-heptane to moles using its molar mass (100.21 g/mol). Next, we multiply the number of moles by the heat of combustion per mole:

• Convert 498 kg to grams: 498,000 g
• Calculate the number of moles: 498,000 g / 100.21 g/mol = 4968.82 mol
• Calculate the heat released: 4968.82 mol × 4817 kJ/mol = 23.92 × 10⁶ kJ

The closest value to 23.92 × 10⁶ kJ among the options is option D) 8.09 × 10⁶ kJ, which means that there is a miscalculation in the provided answer options. None of the options correctly represents the calculated value of × 10⁶ kJ.