Multiple Choice
Consider the following reaction at 298 K: 2H2(g) + O2(g) → 2H2O(l). Which of the following statements is correct regarding the enthalpy change (ΔH) for this reaction?
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8. Thermochemistry
Thermochemical Equations
Multiple Choice
Consider the following reaction:
2 C6H6 (l) + 15 O2 (g) → 12 CO2 (g) + 6 H2O (g) ∆Hº = – 6278 kJ
What volume of benzene (C6H6, d = 0.880 g/mL, molar mass = 78.11 g/mol) is necessary to evolve 5.19 x 109 kJ of heat?
A
1.47 x 108 mL
B
5.19 x 109 mL
C
7.34 x 107 mL
D
9.51 x 109 mL
Verified step by step guidance1
Identify the given data: The reaction releases 6278 kJ of heat per 2 moles of C6H6. We need to find the volume of C6H6 required to release 5.19 x 10^9 kJ of heat.
Calculate the moles of C6H6 needed to release 5.19 x 10^9 kJ of heat using the ratio from the reaction's enthalpy change: \( \frac{5.19 \times 10^9 \text{kJ}}{6278 \text{kJ}} \times 2 \text{ moles of C6H6} \).
Convert the moles of C6H6 to grams using its molar mass: \( \text{moles of C6H6} \times 78.11 \text{ g/mol} \).
Convert the mass of C6H6 to volume using its density: \( \frac{\text{mass of C6H6}}{0.880 \text{ g/mL}} \).
The calculated volume will give you the amount of benzene needed to evolve 5.19 x 10^9 kJ of heat. Compare this volume with the given options to find the correct answer.
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