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Topic: AP chemistry Buffer help please  (Read 8040 times)

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Offline seekeroftruth13

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AP chemistry Buffer help please
« on: February 23, 2011, 11:05:37 PM »
117) A 1 L buffer solution initially contains .025 mol of NH3 and .025 mol of NH4Cl. In order to adjust the buffer pH to 8.75, should you add NaOH or HCL to the buffer mixture? What mass of the correct reagent should you add?

I really don't understand this, the answer is HCl, 4.7g

Offline rabolisk

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Re: AP chemistry Buffer help please
« Reply #1 on: February 23, 2011, 11:21:14 PM »
What about it do you not understand? Give us your line of thought (you must have some idea).

Offline seekeroftruth13

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Re: AP chemistry Buffer help please
« Reply #2 on: February 23, 2011, 11:31:13 PM »
okay so I need to set up the equation but I'm not sure how. we learned this last week and it was so hectic (ppl going in and out for certain events, teacher being absent, me being absent) that I am confused.

Is the equation:

NH3 + h2O forward/backward NH4+ + OH- ?

Offline seekeroftruth13

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Re: AP chemistry Buffer help please
« Reply #3 on: February 23, 2011, 11:33:54 PM »
am I always supposed to add H2O?

Offline rabolisk

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Re: AP chemistry Buffer help please
« Reply #4 on: February 23, 2011, 11:51:48 PM »

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