Ask Question
15 July, 23:26

When a 3.80-g sample of liquid octane (c8h18) is burned in a bomb calorimeter, the temperature of the calorimeter rises by 27.3 °c. the heat capacity of the calorimeter, measured in a separate experiment, is 6.18 kj>°c. determine the δe for octane combustion in units of kj>mol octane?

+1
Answers (2)
  1. 15 July, 23:43
    0
    Answer is: the δe for octane combustion is - 5112.42 kJ/mol.

    Chemical reaction: C₈H₁₈ + 25/2O₂ → 8CO₂ + 9H₂O.

    m (C₈H₁₈) = 3.80 g; mass of octane.

    n (C₈H₁₈) = m (C₈H₁₈) : M (C₈H₁₈).

    n (C₈H₁₈) = 3.8 g : 114 g/mol.

    n (C₈H₁₈) = 0.033 mol; amount of octane.

    cp = 6.18 kJ/°C, specific heat capacity of the bomb calorimeter.

    Qcal = ΔT · cp.

    Qcal = 27.3°C · 6.18 kJ/°C.

    Qcal = 168.71 kJ; amount of heat absorbed.

    ΔE = Qcal : n (C₈H₁₈).

    ΔE = 168.71 kJ : 0.033 mol.

    ΔE = 5112.42 kJ/mol.
  2. 15 July, 23:50
    0
    Heat released from combustion of octane = heat absorbed by calorimeter = heat capacity * temperature change = 6.18 kJ/C * 27.3 C = 169 kJ

    Molar mass of octane = 8 * 12.01 g/mol + 18 * 1.01 g/mol = 114.26 g/mol

    Moles octane burned = 3.80 grams * 1 mol / 114.26 grams = 0.0333 mol octane

    0.0333 mol octane released 169 kJ of heat, heat of combustion is 169 kJ / 0.0333 mol, or 5080 kJ/mol
Know the Answer?
Not Sure About the Answer?
Find an answer to your question 👍 “When a 3.80-g sample of liquid octane (c8h18) is burned in a bomb calorimeter, the temperature of the calorimeter rises by 27.3 °c. the ...” in 📗 Chemistry if the answers seem to be not correct or there’s no answer. Try a smart search to find answers to similar questions.
Search for Other Answers