The heat of combustion of ethane, C2H6, is 1560 kJ/mol. What is the heat of combustion of ethane, in kJ per gram?

Question

BlackTom AI · Accepted Answer

Question restatement: The heat of combustion of ethane, C2H6, is 1560 kJ/mol. What is the heat of combustion of ethane, in kJ per gram?

Option analysis:
1) 4.69 × 10^4 kJ/g
This value is extremely large for a per-gram heat of combustion. To get such a figure, one would have to divide by a very small molar mass or misapply units. Since the molar mass of ethane is about 30 g/mol, the correct per-gram value should be on the order of tens of kJ per gram, not tens of thousands. Therefore this option is incorrect.

2) 9.39 × 10^26 kJ/g
This is an astronomical number and clearly unphysical for a chemical thermodynamics quantity per gram. The calculation would require an utterly erroneous conversion factor or exponent. In context, this option is obviously wrong.

3) 51.9 kJ/g
This is of the correct order of magnitude. The heat of combustion per mole is 1560 kJ per 30.068 g (molar mass of C2H6 ≈ 30.07 g/mol). Doing the division 1560 kJ/mol ÷ 30.07 g/mol gives approximately 51.8–51.9 kJ/g. This matches the given choice and aligns with standard unit conversions for heats of combustion.

4) 195 kJ/g
This value is somewhat higher than the calculated 51.8–51.9 kJ/g and suggests a miscalculation, such as dividing by an underestimated molar mass or mixing up units. Since the molar mass is around 30 g/mol, 195 kJ/g would require 1560 kJ per 8 g, which is inconsistent with the actual molar mass of ethane. Hence this option is incorrect.

CHE 1V_SS1 2025 Final Exam_SS1_2025_Proctored

The heat of combustion of ethane, C2H6, is 1560 kJ/mol. What is the heat of combustion of ethane, in kJ per gram?

查看解析

登录即可查看完整答案

类似问题

Consider the equilibrium dissociation of N2O4(g) to NO2(g). N2O4(g) ⇌ 2NO2(g) Using your knowledge of Lewis structures and bond energies (bond breaking vs. bond forming) to predict whether this reaction is

Calculate H for the reaction of sulfur dioxide with oxygen. 2SO(g) + O(g) 2SO(g) (HSO(g) = –296.8 kJ/mol; HSO(g) = –395.7 kJ/mol)

Calculate the energy required to produce 7.00 mol ClO on the basis of the following balanced equation. 2Cl(g) + 7O(g) + 130 kcal 2ClO(g)

The amount of heat released by the complete burning of 1 mole of a substance is its ____.

One mole of hydrogen is burned in oxygen to produce water in the gas phase, H = 285.8 kJ. What is the energy change when 1 mole of water, in the gas phase, decomposes to form hydrogen and oxygen?

更多留学生实用工具

考试浏览器助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单