00:01
Our chemical reaction is going to be the dimethylamine, ch3 ,2, nh, reacting with the perchloric acid, a strong acid, hclo4, to produce the dimethylammonium ion, ch3 ,2, nh2 +, and the perchlorate ion, the stoichiometry being 1 to 1.
00:34
First we need to calculate the equivalence point volume.
00:37
We're starting with 22 .3 milliliters of the dimethylamine.
00:44
If we convert that into liters, we can then convert the liters into moles of dimethylamine using its molarity.
00:55
One liter contains 0 .315 moles at 0 .315 molar.
01:03
The stoichiometry is 1 to 1, where 1 mole of the dimethylamine reacts with 1 mole of the perchloric acid.
01:13
Then we go to liters of the perchloric acid solution using its molarity.
01:18
One liter contains 0 .319 moles at 0 .319 molar.
01:25
Then last of all, we convert that back into milliliters by multiplying by a thousand and we'll need 22 .02 or just 22 .0 milliliters of the hclo4 solution.
01:45
Then we can determine the concentration of the conjugate acid formed.
01:53
The concentration of the conjugate acid formed at the equivalence point will tell us or can be used to determine the ph at the equivalence point this will be equal to the moles of the dimethylamine we start with because every mole we start with produces a mole of the dimethylammonium ion so if we take our starting volume divided by a thousand convert to moles and then recognize that one mole dimethylamine produces one mole of the dimethylammonium ion.
02:34
This will give us moles dimethylammonium ion.
02:39
We then divide that by the new total volume which will be the 22 milliliters converted to liters plus the 22 .3 milliliters converted to liters giving us 44 .32 or just 44 .3 total milliliters or 0 .0443 liters and the the concentration of the dimethylammonium ion at the equivalence point is 0 .158 molar...