Concept explainers
(a)
Interpretation:
By using the given data, high heating value (HHV) vs molar mass of hydrocarbon graph has to be drawn and also the HHV for propane has to be calculated by using that graph.
(a)
Explanation of Solution
Figure 1
Calculate the HHV for propane by using the trend line equation,
(b)
Interpretation:
By using the given data, High heating value (HHV) - low heating value (LHV) vs molar mass of hydrocarbon graph has to be drawn and also the
(b)
Explanation of Solution
Figure 2
Calculate the
(c)
Interpretation:
By using the given and obtained data in part (a) and part (b), enthalpies of reaction for the given reaction has to be calculated.
(c)
Explanation of Solution
Given reaction
Covert
The second equation corresponds to propane’s LHV. Using
Given reaction
Covert
The estimated enthalpies are
(d)
Interpretation:
By using the given data and results obtained in part (c), the amount of heat energy released when
(d)
Answer to Problem 6.161QP
The amount of heat energy released from the combustion of
Explanation of Solution
Given information,
Use the enthalpy change associated with the LHV based thermochemical equation to calculate the heat energy,
The amount of heat energy released when
(e)
Interpretation:
Estimated results in part (d) has to be compared with accepted thermochemical heats of formation tabulated in appendix C.
Concept introduction:
Hess’s law:
This law is also known as Hess’s law of heat of summation.
This law states that, the sum of enthalpy changes for the individual steps will give the enthalpy change for the overall reaction.
The enthalpy change for the overall chemical change is the same.
(e)
Explanation of Solution
Calculate the enthalpy change using thermochemical heats of formation values
The accepted LHV- based thermochemical equation is
Calculate the heat energy when combustion of
To two significant figures, the obtained value is the same as that calculated in part (d) so the percentage difference is negligible.
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Chapter 6 Solutions
Lab Manual Experiments in General Chemistry
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