00:01
Hello.
00:02
In this question, we have a hydrate that we're working with.
00:06
It is copper sulfate, and we don't know how many water molecules are associated with it.
00:16
This is the formula for the hydrate, and we are trying to find the value of n.
00:21
Or in other words, as the question is written, it wants the ratio of h -2o to cu -s -o -4.
00:32
And we know that by mass, the percent of the water, is 36 .08%.
00:40
That means the balance, in other words, 100 % minus 36 .08 % is the percent of the copper sulfate.
00:50
So if we take 100 % and subtract 36 .08%, we get the copper to be 63 .92%.
01:05
All right.
01:12
So this is the percent.
01:15
These are the percents that we have.
01:16
We have a percent ratio by mass, but mass doesn't do much for us.
01:21
We need moles.
01:22
We need a mole ratio.
01:24
So we need to convert grams to moles.
01:28
Well, we have percents right now.
01:29
We need to get to grams.
01:32
So since we have percent composition, that is going to hold true for any size sample.
01:38
So to determine the number of grams of each that i have, i am going to just select a 100 gram sample, because that is going to make the conversion from percents to mass very easy.
01:56
Because if 36 .08 % by mass is water and it's 100 grams, 36 .08 % of 100 is 36 .08 grams.
02:11
So we have that many grams of water.
02:13
In other words, we're simply changing the percent to a gram sign by assuming 100 gram sample.
02:19
That means in that same 100 gram sample, 63 .92 grams, would be the copper sulfate...