A 1.50 -g sample of quinone $\left(\mathrm{C}_{6} \mathrm{H}_{4} \mathrm{O}_{2}\right)$ is burned in a bomb calorimeter whose total heat capacity is \(8.500 \mathrm{~kJ} /{ }^{\circ} \mathrm{C}\). The temperature of the calorimeter increases from 25.00 to \(29.49^{\circ} \mathrm{C}\). (a) Write a balanced chemical equation for the bomb calorimeter reaction. (b) What is the heat of combustion per gram of quinone and per mole of quinone?

Short Answer

Expert verified
The balanced chemical equation for the combustion of quinone is: C₆H₄O₂ + 6O₂ → 6CO₂ + 2H₂O. The heat of combustion per gram of quinone is 25.443 kJ/g, and per mole of quinone is 2748.499 kJ/mol.

Step by step solution

01

(a) Balanced chemical equation

To write a balanced chemical equation for the combustion of quinone in a bomb calorimeter, we need to know that quinone reacts with oxygen (O₂) during combustion and produces carbon dioxide (CO₂) and water (H₂O). The unbalanced equation for this reaction is as follows: C₆H₄O₂ + O₂ → CO₂ + H₂O Now we will balance the equation: C₆H₄O₂ + 6O₂ → 6CO₂ + 2H₂O So, the balanced chemical equation for the combustion of quinone is: C₆H₄O₂ + 6O₂ → 6CO₂ + 2H₂O
02

(b) Heat of combustion calculation

To calculate the heat of combustion of quinone, we will use the equation: q = C × ΔT Where q is the heat released during combustion, C is the heat capacity of the bomb calorimeter, and ΔT is the temperature change in the bomb calorimeter. Given values are: C = 8.5 kJ/ºC ΔT = 29.49ºC - 25.00ºC = 4.49ºC Now we will calculate the heat released during combustion (q): q = C × ΔT q = 8.5 kJ/ºC × 4.49ºC q = 38.165 kJ Now we will find the heat of combustion per gram and per mole of quinone: 1. Heat of combustion per gram (q/g): Divide the heat released during combustion (q) by the mass of the quinone sample. q/g = q / mass q/g = 38.165 kJ / 1.50 g q/g = 25.443 kJ/g 2. Heat of combustion per mole (q/mol): First, we need to determine the molar mass of quinone. Quinone: C₆H₄O₂ Molar mass: (6 × 12.01) + (4 × 1.01) + (2 × 16.00) = 108.05 g/mol Now we will calculate the heat of combustion per mole by dividing the heat released during combustion (q) by the moles of quinone sample. Moles of quinone = mass / molar mass Moles of quinone = 1.50 g / 108.05 g/mol Moles of quinone = 0.01388 mol q/mol = q / moles of quinone q/mol = 38.165 kJ / 0.01388 mol q/mol = 2748.499 kJ/mol So, the heat of combustion per gram of quinone is 25.443 kJ/g, and per mole of quinone is 2748.499 kJ/mol.

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