The heat of combustion for 1 mole of carbon to carbon dioxide is -410 kJ. How many kJ of heat would be liberated from the complete combustion of 60.0 g of carbon?
Correct answer: B. -2050 kJ
- A. -82 kJ
- B. -2050 kJ
- C. -24,600 kJ
- D. None
Explanation
To solve this question, first convert the mass of carbon to moles. The molar mass of carbon is approximately 12.01 g/mol. Thus, 60.0 g of carbon is equivalent to 60.0 g / 12.01 g/mol ≈ 5.00 moles of carbon. Since the heat of combustion for 1 mole of carbon is -410 kJ, the total heat liberated from 5.00 moles would be 5.00 moles × (-410 kJ/mol) = -2050 kJ. Therefore, the correct answer is Option B.Option A is incorrect because it results from an incorrect calculation with a much smaller value of heat. Option C is incorrect because it assumes an unrealistic or erroneous multiplication factor. Option D is incorrect because it suggests that the correct answer is not listed, which is not the case here.
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Thermochemistry measures energy changes in chemical reactions and distinguishes exothermic from endothermic processes. Work covers systems, surroundings and state functions, internal energy, the first law of thermodynamics, enthalpy and Hess's law, including the sign conventions used when heat enters or leaves a system.
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