Stock Solution? - C& OCR 21st Century

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I was doing a past paper, and it came up with something about stock solutions. Here is the original question:

A student uses titration with nitric acid to find the concentration of a solution of sodium hydroxide.

a) The student has a stock solution of nitric acid containing 63g in ech dm3.

She uses this to make 250 cm cubed of a standard solution containing 6.3g in each dm cubed.

Describe how she makes up this solution. (dm3 = 1000cm3)

Thank you.

Posted Wed 25th May, 2011 @ 11:28 by Oliver

2 Answers

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1)Fill a burette with the alkali sodium hyrodixe and take an initial reading of the volume.

2)Accurately weight out a [insert number]gram sample of solid citric acid and dissolve it in [insert number] cm3 of distilled water

3)Use a pipette to measure 25cm3 of the aqeuous citric acid and put it into a concial flask.
Add a few drops of the indicator, phenolphthalein, to the concial flask.

4) Add the alkali from the burette to the acid in the flask drop by drop
Swirl the flask to ensure it mixes well.
Keep swirling and adding the alkali until it is pink
Record the volume of alkali added by the subracting the amount in the hurette at the end of the starting value.

Repeat the whole procedure until you get two results that are the same.

(I got this from my revision guide, hope it sort of helps!) (: x

Answered Wed 25th May, 2011 @ 11:46 by Shannon
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That doesn't anaswer the question though? How would that gain the studen 250 cm cubed of standard solution?

Nevermind, I worked it out. 6.3g is 63/10, so find 1/10 of 250 which = 25. Then add 225 cm3 of distilled water.

Answered Wed 25th May, 2011 @ 12:34 by Oliver