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QCE Chemistry Questions Thread
aleenabinu:
--- Quote from: sweetcheeks on April 19, 2020, 10:35:36 pm ---I wouldn't be so sure that those results are too low. What are you comparing them to?
Think about the pH of lemons and lemon juice and relate that to the H+ concentration. Keep in mind, ascorbic acid is a weak acid, and the pH is buffered, but none-the-less you can get an approximate value.
--- End quote ---
Thank you for replying!
I am comparing them to the recommended daily amount.
These are my calculations. Could you please tell me if i went wrong in any places? Thank youuu :)
Bri MT:
--- Quote from: aleenabinu on April 21, 2020, 05:14:32 pm ---Thank you for replying!
I am comparing them to the recommended daily amount.
These are my calculations. Could you please tell me if i went wrong in any places? Thank youuu :)
--- End quote ---
Hey!
There's some places where I can't check your work because, for example, I don't know what your concordant titres actually were.
One thing that did stand out is the concentrations of iodine you plugged into n=cv. Was this 0.005 M or 5 M? The reason you divide the volume by 1000 for the titres is because they're in mL and you need to convert them to L; if your concentration was 5.00 M you should not be dividing that by 1000. Aside from that, I can't see any alarm bells in your calculations, though my personal preference would be for your molar ratio (the unknown/known fraction) to be specific to the molecules you were working with.
Good luck & I hope you found this helpful :)
aleenabinu:
--- Quote from: Bri MT on April 22, 2020, 01:22:58 pm ---Hey!
There's some places where I can't check your work because, for example, I don't know what your concordant titres actually were.
One thing that did stand out is the concentrations of iodine you plugged into n=cv. Was this 0.005 M or 5 M? The reason you divide the volume by 1000 for the titres is because they're in mL and you need to convert them to L; if your concentration was 5.00 M you should not be dividing that by 1000. Aside from that, I can't see any alarm bells in your calculations, though my personal preference would be for your molar ratio (the unknown/known fraction) to be specific to the molecules you were working with.
Good luck & I hope you found this helpful :)
--- End quote ---
Thank you!! My teacher checked it and she said it looks fine.
One more question. Im comparing my concentrations to the recommended daily amount. I just realised that they're all in mg. I know you can convert concentration to mg, but that would just be for that quantity of sample. Is there a way i could convert it and obtain more accurate results?
Bri MT:
--- Quote from: aleenabinu on April 25, 2020, 05:54:44 pm ---Thank you!! My teacher checked it and she said it looks fine.
One more question. Im comparing my concentrations to the recommended daily amount. I just realised that they're all in mg. I know you can convert concentration to mg, but that would just be for that quantity of sample. Is there a way i could convert it and obtain more accurate results?
--- End quote ---
No worries!
hmmm... I'm not sure what question you're trying to answer, but you could consider converting the RDI to mol, then use that to find the volume of lemon juice required to meet the RDI based on your concentration calculation. This wouldn't make your results more accurate but it could increase your ability to analyse the relationship in a valid way
aleenabinu:
--- Quote from: Bri MT on April 25, 2020, 07:33:17 pm ---No worries!
hmmm... I'm not sure what question you're trying to answer, but you could consider converting the RDI to mol, then use that to find the volume of lemon juice required to meet the RDI based on your concentration calculation. This wouldn't make your results more accurate but it could increase your ability to analyse the relationship in a valid way
--- End quote ---
thank you sm!! this helped alot.
as i am just determining the concentration of ascorbic acid in fresh lemon and bottled lemon juice, would i need to graph anything? now that i think about it, it wouldve been smart to record the pH but we didn't. or could i just insert a table with intial, final readings and tire volume and still get top marks in that criteria?
is iodine a weak or strong base? i can't find an exact answer anywhere :(
also, when explaining about the relationship, what actually is the relationship in this case? as more standard solution is added, more closer to the end point ? i dont knowww :-\
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