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Module 4 AQA - 2 questions

Hiya
Please can comeone help me with this question on calculating the maximum possible yield. I have no idea were to begin with it.

Calculate the maximum possible yield of nitrobenzene starting from 5.0g of benzene.

And also this question
The enthalpy of hydrogenation of cyclohexene is -119.6kj mol^-1. use this info to calculate the enthalpy of hydrogenation of the hypothetical molecule
cyclohexa-1,3,5-triene.
Again I have no idea were to start.

Thanks for any help.

Reply 1

charco

Study Forum Helper

Write out the equations for the formation of nitrobenzene.
Calculate how many moles of benzene you start with.
Use the equation to decide how many moles of nitrobenzene you finish with.
Use the RMM of nitrobenzene to find the number of grams from the number of moles - this is the theoretical yield.
Now look at the actual mass that you obtain - is it the same?
No, so you now find out the percentage yield by:
(actual mass/theoretical mass) x 100