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March 31, 2026, 10:07:43 am
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Author Topic: Interesting questions (chem)  (Read 7707 times)  Share 

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qshyrn

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Re: Interesting questions (chem)
« Reply #30 on: November 07, 2010, 09:23:32 pm »
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Quote from: Martoman on November 06, 2010, 11:49:44 pm
lol, well i knew this at an intuitive level but i found it lovely as a question.

Similarly:

NaOH Has a pH 13 in a solution. How much HNO3 must be added so the solution reaches pH 1?
can you give us the solution to this?
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m@tty

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Re: Interesting questions (chem)
« Reply #31 on: November 07, 2010, 09:32:40 pm »
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Quote from: Martoman on November 06, 2010, 11:49:44 pm
lol, well i knew this at an intuitive level but i found it lovely as a question.

Similarly:

NaOH Has a pH 13 in a solution. How much HNO3 must be added so the solution reaches pH 1?

It depends on the volume of the solution.

But..

Final

Initial







Don't have my data book with me..

That's all I can think of. =\

Nothing elegant about it though, unlike what I'd expect with one of your interesting questions...

I am an idiot  .. ..
« Last Edit: November 07, 2010, 10:08:03 pm by m@tty »
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Martoman

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Re: Interesting questions (chem)
« Reply #32 on: November 07, 2010, 09:37:41 pm »
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Quote from: qshyrn on November 07, 2010, 09:23:32 pm
Quote from: Martoman on November 06, 2010, 11:49:44 pm
lol, well i knew this at an intuitive level but i found it lovely as a question.

Similarly:

NaOH Has a pH 13 in a solution. How much HNO3 must be added so the solution reaches pH 1?
can you give us the solution to this?

awwww i'll pm you let the others have a go.



Quote from: m@tty on November 07, 2010, 09:32:40 pm
Quote from: Martoman on November 06, 2010, 11:49:44 pm
lol, well i knew this at an intuitive level but i found it lovely as a question.

Similarly:

NaOH Has a pH 13 in a solution. How much HNO3 must be added so the solution reaches pH 1?

It depends on the volume of the solution.

But..

Final

Initial







Don't have my data book with me..

That's all I can think of. =\

Nothing elegant about it though, unlike what I'd expect with one of your interesting questions...

HNO3 is a strong acid lol. You don't have HNO3 in data book so nerrrhhhhhhh  :smitten:

There is a beautifully elegant 2 line solution to this
« Last Edit: November 07, 2010, 09:39:16 pm by Martoman »
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m@tty

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Re: Interesting questions (chem)
« Reply #33 on: November 07, 2010, 09:41:22 pm »
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Is it? I can never remember.. I always just check to see if it's in the data book, if it isn't then I assume it's a strong acid.

Ok then, since it's a strong acid:

..

EDIT:
Cut out the crap about   and it's two lines ::)
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Martoman

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Re: Interesting questions (chem)
« Reply #34 on: November 07, 2010, 09:43:30 pm »
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no.  :P

assume you have a 1L solution as well if that helps
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m@tty

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Re: Interesting questions (chem)
« Reply #35 on: November 07, 2010, 09:49:52 pm »
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Are you saying my answer is wrong, or that there is a more elegant solution? ..

I don't see a problem in my logic??
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fady_22

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Re: Interesting questions (chem)
« Reply #36 on: November 07, 2010, 09:56:37 pm »
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Isn't it just twice the volume (of the same concentration acid)?
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Martoman

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Re: Interesting questions (chem)
« Reply #37 on: November 07, 2010, 09:57:15 pm »
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I think the fault lies in a simlar case where:

What is the Ph of HCL at concentration 10^-14?

so [h+] = 10^-14 but ph doesn't = 14.

Its 7ish not 14.
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Martoman

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Re: Interesting questions (chem)
« Reply #38 on: November 07, 2010, 09:57:55 pm »
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Quote from: fady_22 on November 07, 2010, 09:56:37 pm
Isn't it just twice the volume (of the same concentration acid)?

What do you mean exactly?
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fady_22

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Re: Interesting questions (chem)
« Reply #39 on: November 07, 2010, 10:00:10 pm »
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I'm wrong. Forget my comment.
I just thought about it again, and it made no sense. :)
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Martoman

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Re: Interesting questions (chem)
« Reply #40 on: November 07, 2010, 10:00:53 pm »
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*shifty eyes* it didn't taste right to me  :police:
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m@tty

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Re: Interesting questions (chem)
« Reply #41 on: November 07, 2010, 10:07:16 pm »
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Oh yeah, ok.



So initial

Final

So you need 0.1 M to neutralise and 0.1 M to make the pH right.

?? ..
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Martoman

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Re: Interesting questions (chem)
« Reply #42 on: November 07, 2010, 10:07:58 pm »
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Exactly.
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bomb

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Re: Interesting questions (chem)
« Reply #43 on: November 07, 2010, 10:09:16 pm »
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Is the answer 0.2mol?

Edit: beaten by m@tty arrgh.
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m@tty

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Re: Interesting questions (chem)
« Reply #44 on: November 07, 2010, 10:11:32 pm »
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Quote from: Martoman on November 07, 2010, 10:07:58 pm
Exactly.

Still don't see anything elegant ..

And lol, I've been trapped by that before. How fail I am. xD
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