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Topic: CHEMISTRY QUESTION- pH - :S help please  (Read 4170 times)

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Offline fatoomy

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CHEMISTRY QUESTION- pH - :S help please
« on: December 15, 2007, 11:13:34 PM »
Hey. I hope you are all doing well. I've been trying to figure this question out and i actually have no idea how to do it. This is just the practice one, but later I have to do the real one at school on monday, but my teacher said that they are similar. I was wondering whether anybody knows how to solve it. Thank you so much for your time :)

X ________________________ X ________________________ X

Killarney Provincial Park is much noted for its rugged beauty and was an inspiration to the Group of 7 painters. Unfortunately most of its lakes have become acidified due to acid rain. Nellie Lak, often described as the clearest lake in the park, is one of the worst off. In 1996 it had a pH of 4.6. Calculate the mass of lime, Ca(OH)2, needed to raise the pH of Neillie lake from 4.6 (when aquatic life cannot survive) to a pH of 6.5 (characteristic of normal aquatic life). The lake has a volume of about 1 x 10^11 litres. (1km wide by 2km long by 50m deep). Assume the acid is HCl.

Offline Yggdrasil

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Re: CHEMISTRY QUESTION- pH - :S help please
« Reply #1 on: December 16, 2007, 12:01:21 AM »
Always start with a balanced chemical reaction.

Offline fatoomy

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Re: CHEMISTRY QUESTION- pH - :S help please
« Reply #2 on: December 16, 2007, 03:24:50 PM »
um okk :S
so it would be:
Ca(OH)2 + HCL --> CaCl + H20

but how does that help u get the mass of lime :S

Offline enahs

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Re: CHEMISTRY QUESTION- pH - :S help please
« Reply #3 on: December 16, 2007, 03:30:43 PM »
Quote
so it would be:
Ca(OH)2 + HCL --> CaCl + H20

That is not balanced.

This page should help you with everything:
http://www.shodor.org/UNChem/basic/stoic/index.html

Offline fatoomy

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Re: CHEMISTRY QUESTION- pH - :S help please
« Reply #4 on: December 16, 2007, 03:33:07 PM »
yikes srry :P forgot about that part && i missed a 2

Ca(OH)2 + 2HCl --> CaCl2 + 2H20

but i still dont get how that can help u figure out the mass of lime using pH

Online Borek

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Re: CHEMISTRY QUESTION- pH - :S help please
« Reply #5 on: December 16, 2007, 05:27:24 PM »
Assuming HCl is the only source of pH - now many moles of HCl in the lake?
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