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QCE Chemistry Questions Thread
A.Rose:
Hello!
I have just started Organic chemistry and I have a quick question on how to draw 4-oxo propyl hexanoate. (The answer from my textbook is attached) I understand the carboxyl group and everything just not the placement of the ketone. Isn't carbon 1 the carbon with the carboxyl group attached? In the answer, I don't know why the ketone is where it is if carbon 1 is where the carboxyl group is. The answer seems to have carbon 1 as the very end carbon...?
Bri MT:
--- Quote from: A.Rose on March 20, 2020, 07:52:42 pm ---Hello!
I have just started Organic chemistry and I have a quick question on how to draw 4-oxo propyl hexanoate. (The answer from my textbook is attached) I understand the carboxyl group and everything just not the placement of the ketone. Isn't carbon 1 the carbon with the carboxyl group attached? In the answer, I don't know why the ketone is where it is if carbon 1 is where the carboxyl group is. The answer seems to have carbon 1 as the very end carbon...?
--- End quote ---
Hey,
Counting starts from the end of a molecule and with the choice of what end being made to lower the numbers you use. I think where you may be getting confused here is reading this as [4-oxo-propyl][hexanoate] and thus counting from the hydroxyl end of the propanol, with that end of the molecule going to the ester functional group. Note in in this question you can't interpret it that way due to the limited number of carbons in propanol.
In this question you need to read it as [4-oxo] [propyl hexanoate]. I.e. the ketone functional group needs to be 4 carbons from the end. You can only do this in the way shown in the textbook answer.
Hope this makes sense!
A.Rose:
Hello
Would someone be able to check my calculation using the Nernst equation? See attached:
Thank you so much!! :D
Bri MT:
Hey,
Plugging in the same values as you used my calculator gave me a slightly different value (1.12016 V) so maybe double check your calculation checking for:
- reading the decimal places carefully
- having a x symbol between the fraction and the log / not using the simplified fraction form. (Some calculators read 3 1/2 as 7/2 or 3 + 1/2 rather than as 3/2 )
Note that some of the values you used had more accuracy than is published in the QCAA formula and data book and so using them for practice questions may produce slightly different results than you would see in suggested solutions
Finally, I recommend losing some of your decimal places as they imply much more accuracy in the data than what you actually have.
Hope this helps!
A.Rose:
Hi!
I have a few questions about my Chemistry Student experiment I am doing at the moment that relates to how I should conclude in regard to the validity of the experimental relationship and what relationship my experimental data is demonstrating; taking in consideration the percentage error in the gradient and possible faults in equipment.
My experiment involved a Daniell cell where I changed the concentration of copper sulphate from 0.25M, 0.5M, 0.75M and 1M and measured the voltage produced. The temperature was at 24 degrees and I used the Nernst equation to obtain the theoretical voltages. The Zinc sulphate was kept constant at 0.1M.
I just thought it would be easier to write my questions on a word doc since they are a bit long and so that I can put my graphs next to my questions.
Thank you so much! :D
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