00:01
Okay, so here we have an equation.
00:03
We want to know how much hydrogen gas is produced from reacting 0 .140 grams of magnesium.
00:11
So we have a pressure and a temperature.
00:14
We have the gas constant.
00:16
And so what this is going to be using is the pv equals nrt equation.
00:20
But we first need to solve for n, the moles of gas that's being produced.
00:25
So to do that, we'll need to balance our equation.
00:27
So to balance the hydrogens, i'm going to put a 2.
00:30
Here and then this changes the chlorine so i'll put a two in front of the mgcl and i'll then balance the magnesium.
00:39
So now everything we have two of each thing on the right and the left so this should be balanced.
00:46
Then to go from grams of magnesium into moles of hydrogen i'm going to need the molar mass of magnesium.
00:59
So if i go to my periodic table one mole of magnesium is a equivalent to 24 .305 grams.
01:14
And then using my balanced equation, i can go from moles of magnesium into moles of hydrogen gas.
01:20
So for every two moles of magnesium, one mole of hydrogen gas is produced.
01:30
So this will tell me how many moles of hydrogen gas i have.
01:34
So 0 .140 divided by 24 .305, divided by 2 is 0 .00289 moles.
01:46
And so now i want to solve for the volume, and i'll use the pv equals nrt equation, and i'm solving for volume.
01:55
So volume is going to be equal to my moles, which i just solved for, times my gas constant, which is 0 .0821.
02:09
My temperature, but we need to make sure all of our units are in the units of the gas constant...