00:01
In this problem, it is asked that how many grams of k -o -h are present in 38 .0 milliliter of a 7 .33 molar k -o -h solution.
00:14
Right.
00:15
So how we give moles.
00:19
Moles is given by moles is equal to molarity into volume, right? so remember, this has to be in liters, right? so here it is we can easily say that here it is equals to polarity is 7 .33 right this is molar into 38 .0 mid later right so when we will multiply it what we will get here let us see so this is giving us 7 .33 into 38 which is nothing but this is equal to 278 .54 right so this is equals to 5 4 this is milly moles so now what we know about it right so here we want to calculate the mass so mass is nothing but this is number of moles into molar mass yes we can write it yes so what is molar mass here? our molar mass is 56 .1056 grams per mole.
01:55
So now this is moles.
01:57
Moles is 278 .54 millimoles.
02:03
Remember this.
02:04
You have to write the units very carefully.
02:08
So here it will give us 278 .54.
02:13
Into 56 .1056 right so this will give us 156 oh i'm sorry 15, 6 .27 .67 .65382 millimoles right so what does milly represent? millie represents 10 to the power minus 3 .6.
02:43
So this will be 10 to be power minus 3 moles.
02:48
That means this will give us 156 or you can say this has to be shifted with 3 decimal places because 102 power minus 3 is there.
03:00
So 15 .67 628 let us say right...