Using data from the titration of a chloride solution with silver nitrate, the steps used in calculating the concentration of chloride are explained.
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0:00here will be given some data from a
0:05titration and ask to use this data to
0:08calculate the concentration of anion in
0:10a sample we'll start by looking at how
0:13we handle titration calculations in
0:15general titration calculations in cam 12
0:19involved the reaction between two
0:21reactants which will call a and B here
0:23in the center of all titration
0:26calculations are the moles of reactants
0:28a and the moles of reactants be we
0:31represent number of moles and chemistry
0:33by the letter and reacting a represents
0:37the reactant that were given enough
0:39information to find the number of moles
0:41of to convert moles of a 2 moles of B we
0:45always use the mole ratio or coefficient
0:48ratio of b2a in the balanced equation
0:51for the titration reaction the
0:54information were given about a could be
0:56the molar concentration of a represented
0:59by the letter C and the volume of a in
1:02leaders represented by the letter B or
1:05it could be the massive a and grams
1:07represented by the letter M whatever
1:11were given step one of a titration
1:13calculation is to convert what were
1:15given two moles of reactants a or na
1:19step 2 of any titration calculation is
1:23to convert moles of reactants a 2 moles
1:26of reactants be this is done using the
1:29mole ratio or coefficient ratio of b2a
1:32in the balanced equation we could be
1:35asked one of three different things for
1:37reactant B we could be given the volume
1:40of B and asked to find its molar
1:42concentration CB we could be given the
1:46concentration of B and asked to find its
1:49volume bb or we could be asked to find
1:52the massive be in Grand step 3 and any
1:56titration calculation is to convert
1:59moles of B to whatever were asked for
2:01concentration of B volume of be more
2:04massive be so here is a generic diagram
2:08that outlines the possible steps to take
2:10in most titration calculation problems
2:13remember the first step is always to
2:16find moles of what we can
2:18let's do an example precipitation
2:22titration question a 50 milliliter
2:24sample of a solution known to contain
2:26fluoride her cl- science is titrated
2:30with point 100 molar agno3 solution a
2:34small amount of sodium chromate is added
2:36to the sample as an indicator three
2:39separate trials are done we're asked to
2:41find the concentration of cl minus in
2:44the original sample the results are
2:47recorded in a table like this
2:49the first thing we need to do is
2:51calculate the volume of a gno three
2:53solution used in each trial we do that
2:57by subtracting the initial be reading
2:59from the final be rereading so in trial
3:02one its 4.46 minus point 95 which is
3:073.51 milliliters for trial to the volume
3:12is 7.65 minus 4.45 which is 3.20
3:18milliliters and in trial three the
3:21volume used his 10.8 7-7 points65 which
3:27is 3.2 two milliliters taking a look at
3:31these three results we see that the
3:33volume used in trial 13.5 one
3:36milliliters is considerably higher than
3:393.20 and 3.22 used in trials two and
3:44three respectively for that reason we
3:47just discard the value of 3.51 we
3:51calculate the best average volume of AGN
3:5403 by taking 3.20 plus 3.22 and dividing
3:59by 2 which gives us 3.21 milliliters
4:03will make a note of the average volume
4:06of 3.21 milliliters appear in the table
4:10will convert the three-point 21
4:12milliliters 2.00 321 leaders at this
4:17point let's dissociate the AGM three
4:20here and we get a G+ and no.3 minus and
4:25will dissociate
4:26the AGM three here also giving us a G+
4:31and no.3 minus the nitrate I and no.3
4:34minus a spectator I it does not form any
4:37precipitates will just discard it so we
4:41can simply say that the concentration of
4:43AG plus his point 100 molar and the
4:48volume of a G+ solution used is equal to
4:51point zero zero 321 leaders so we have
4:55all the information we need up here now
4:57we'll just rearrange it a bit so it
5:00looks like this we have the
5:02concentration of a G+ and the volume of
5:05a G+ here and the volume of co- here at
5:10this point will convert the 50
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