Please add your final values of a) q (in J) and b) ΔH (in kJ/mol) for the combustion of hexane that you will have calculated following our practical in Monday's lesson, by writing a new comment to this post.
Once we have all 6 values of q and ΔH (one set of values from each pair), we can calculate the average and think about how close our values are to a) each other and b) the theoretical value, suggesting reasons for any differences.
Please make sure that your pair's q and ΔH values are added to this post by the end of Wednesday, 28th November.
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5 comments:
I'm trying to get the results from our experiment from Sam Proehl.
In the meantime, I'm struggling with the homework. For part b) of the sheet headed 'Enthalpy Calculations', is m the mass of the sodium hydroxide or the sulphuric acid?
Thanks for your comment, Carina.
In q=mcT, 'm' is always the TOTAL mass of the solution, which we approximate is the same as the total volume of the solution. In this case, this will mean the combined volumes of sodium hydroxide and sulphuric acid.
When you are asked to convert 'q' into the enthalpy change (in kJ/mol), it will specify per mole of which substance. For this question it says "per mole of sulphuric acid" so you'll work out the number of moles of sulphuric acid involved in the reaction and then use it to calculate the enthalpy change.
I hope this helps!
hey, mine and Alex's results were:
q = 20054 J
-893 KJmol
will we be able to get some more practice questions on the q = mcΔT because i need to practice it more
Ben
Thanks! :)
I've handed the sheet in today, so I'll print out another and have another go.
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