00:01
So students for this problem we have a reaction between magnesium and hydrochloric acid.
00:08
So we expect magnesium chloride and hydrogen gas.
00:15
As you can see this is a solid there.
00:20
We have aqueous so we put two there and a solid.
00:24
So that's what we expect here.
00:26
And we have 80 ml of the acid which shows ph is negative 0 .544.
00:40
So the first step is to determine the concentration of the acid, molarity.
00:51
So therefore we know that we're looking for concentrations of hydrogen ions.
00:55
So this is log inverse of negative 0 .544.
01:08
So we're looking at a 3 .5 molar concentration.
01:15
Because otherwise we know that concentration of hydrogen is the same as concentration of acid.
01:22
Now the next stage is to determine molarity because the number of moles of solute is given in one liter.
01:35
So we determine the number of moles of the acid.
01:40
So moles hydrochloric acid will be the concentration multiplied by the volume 80 divided by 1000 to make 13 liters.
01:49
So we expect 0 .28 moles of the acid.
01:57
Now because mole ratio of acid and the solid is 2 to 1.
02:04
So we have a 2 and 1 ratio here.
02:08
So we expect that the moles of magnesium will be twice that of hydrochloric acid...