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Topic: Nutrition chemistry help  (Read 2558 times)

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Offline 14035253K

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Nutrition chemistry help
« on: March 02, 2016, 08:50:35 AM »
Hi,

I am currently studying for a nutrition degree and need a little help with some chem for a practical.

We were not given apparatus to test ph, (they forgot it) but we are still expected to know the ph.

Could anyone please help and tell me the ph of  following solutions and a brief description of how they got there.

All in aqueous solution
Baking soda 1% 2% 3%
Vinegar (diluted acetic acid) 1% 2% 3%
NaCl 1% 2% 3%
The water we used was not distilled, it was boiled tap water so I am guessing that they don't want exact figures.
I have no idea where to start....

Thanks

Offline Babcock_Hall

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Re: Nutrition chemistry help
« Reply #1 on: March 02, 2016, 09:58:52 AM »
It is a forum rule that you must show your attempt or your thoughts before we can help you. One way for you to begin might be to talk about your expectations in a qualitative sense.

Offline Arkcon

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Re: Nutrition chemistry help
« Reply #2 on: March 02, 2016, 11:02:00 AM »
Hi,

I am currently studying for a nutrition degree and need a little help with some chem for a practical.

Sure, glad to help.

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We were not given apparatus to test ph, (they forgot it) but we are still expected to know the ph.

Well, that just simply sounds awful. 

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Could anyone please help and tell me the ph of  following solutions and a brief description of how they got there.

As has already been mentioned, we'd like to see your attempt first.  Please read the Forum Rules{click}.  Perhaps, "how they got there" is a topic covered in your current textbook.  Or maybe not, this is a more typical undergraduate chemistry course concept.  Perhaps this is in another textbook, you may read soon, or were expected to have covered first. 

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All in aqueous solution

Aqueous solution is pretty much the only solution for which pH is valid.

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Baking soda 1% 2% 3%
Vinegar (diluted acetic acid) 1% 2% 3%
NaCl 1% 2% 3%

Maybe you can Google each of these to understand their nature for yourself.

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The water we used was not distilled, it was boiled tap water so I am guessing that they don't want exact figures.

OK, that kinda ruins a calculating method, but then, they likely want a general answer.

Quote
I have no idea where to start....

Maybe the laboratory description or your recent textbook studies have some hints for you.
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline 14035253K

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Re: Nutrition chemistry help
« Reply #3 on: March 02, 2016, 04:54:48 PM »
Well I am guessing that the vinger is acidic, baking soda alkaline and salt I was assuming alkaline. I Googled this and found tonnes of formulas to work it out but I have not completed chemistry or maths past a high school level. I also have dyslexia, dsycalculus and specific learning disorder, so it is very hard for me to just get complex mathematical equations. :-( I don't know where to even start.

Offline Arkcon

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Re: Nutrition chemistry help
« Reply #4 on: March 02, 2016, 05:22:35 PM »
Then the best answer that you personally can give will likely be an essay summarizing the points you've mentioned just now.  If you can support your points,you may get some credit.  As I said, using non-purified water will hamper the accuracy of a calculated result.  And you have a great deal of calculations to do to convert your measured quantities into useful values for further calculation. By the time you're done with your essay, they may have bought a pH meter.
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline Babcock_Hall

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Re: Nutrition chemistry help
« Reply #5 on: March 02, 2016, 06:24:15 PM »
What makes you think that table salt is alkaline?

Offline 14035253K

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Re: Nutrition chemistry help
« Reply #6 on: March 03, 2016, 05:19:24 AM »
I thought salt might be alkaline because you can bathe wounds in it and I thought acid would burn on open skin. I just need a general figure for each but it seems there is no data for it without tonnes of maths. I probably don't need the exact ph but I am achieving a first this semester and didn't want my lack of organic chemistry to bring down my grade.

Offline Arkcon

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Re: Nutrition chemistry help
« Reply #7 on: March 03, 2016, 06:55:43 AM »
Please read the Forum Rules{click} carefully, you are violating them repeatedly.  Please do some research in textbooks and your class notes.  Please don't try to justify, in open forum discussion, your need for the 'bestest' grade or your personal problems, as the reason why we must do it all for you.  Such behavior is offputting, when it happens between adults, and may cause you to suffer an unpleasant response, either here on the Chemical forums, or even in real life.

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I thought salt might be alkaline because you can bathe wounds in it and I thought acid would burn on open skin.

Briefly, your statement is wrong.  This is basic, high school level or even junior high school level,  chemistry.  I'm sorry you've missed out on such instruction, but your status now is what you (and all of us) have to work with.  You could write an essay trying to justify your conclusion, but I also think its too lacking, and will likewise cost you points.

Try to think about in in some other way, since you're lacking chemistry to work with.  And clearly, the class instructor doesn't mind that you lack basic chemistry, if this is how the class is taught.  Are all acids dangerous to skin and wounds?  Is your vinegar that dangerous? Since baking soda is alkaline, is tables salt the same sort of compound?  Try to guess the project logically:  they've given you an acid, a base and ...another base?  Maybe they wouldn't do that?
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline Burner

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Re: Nutrition chemistry help
« Reply #8 on: March 03, 2016, 07:26:59 AM »
I thought salt might be alkaline because you can bathe wounds in it and I thought acid would burn on open skin.

Are you thinking about whether NaCl is an acidic salt, neutral salt or alkaline salt? Or you think that NaCl is an alkali?

I just need a general figure for each but it seems there is no data for it without tonnes of maths. I probably don't need the exact ph but I am achieving a first this semester and didn't want my lack of organic chemistry to bring down my grade.

Why does the question/scenario/objective exactly ask for? Are you required the find out the value of pH of the solutions, or just arrange the solutions in ascending/descending order of pH? Do you have any sorts of worksheets to fill in after the lab?
Year 1 science student in HKUST and a Chemistry geek.
If I make any mistakes in the forum, please don't hesitate to correct me as I want to learn.

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