00:01
We are told metallic magnesium reacts with steam to produce magnesium hydroxide.
00:18
I'm going to assume that's a q plus h2 gas.
00:26
If 16 .2 grams of magnesium are heated with 12 .0 grams of h2o, we're asked to find the limiting reactant, the moles of excess, reactant and grams of product.
01:14
I'll do these two first and we'll do those by employing a simple mass mass stochometric conversion.
01:26
Okay, magnesium is 24 .31 i believe for an atomic mass.
01:40
Let me make sure i have a balanced chemical equation here.
01:44
It looks like i will need a two here.
01:49
2 -4 -24 -2 -2 -2.
01:52
Okay.
01:54
So i have a one -to -one mole ratio.
01:59
Let me read my question again.
02:01
How many grams of each product? so i'll do this one first.
02:27
And then my molar mass of mgoh.
02:30
Let's see if i have a molar mass tab open.
02:32
I usually do, but it appears i don't.
02:42
Molar mass of magnesium hydroxide is 58 .32.
03:01
And that will equal 16 .2.
03:05
Times 58 .32 divided by 24 .31.
03:12
If this is limiting, i would have 38 .9.
03:23
Now let's do the same type of calculation, except this time we'll be using water as our initial substance.
03:33
I will use a 2 to 1 mole ratio of water to magnesium hydroxide.
03:41
I keep wanting to put magnesium in parentheses.
03:47
And that molar mass of magnesium hydroxide remains at 58 .32.
04:03
This will equal 12 times 58 .32 divided by 18 .02 divided by 2.
04:12
And i will have 19 .4 grams of magnesium hydroxide.
04:23
Okay, let me see, the grams of each product form.
04:26
So somebody came to the door, so i stopped this, got to figure out where i was.
04:32
So my limiting reactant is water.
04:46
For products formed, we will have 19 .4 grams of magnesium hydroxide.
05:05
Next, i have to also report grams of h2.
05:09
And i'll do that calculation right now.
05:13
12 .0 grams of water.
05:18
And i'm just going to run through a similar calculation here.
05:21
The only thing that will change is my molar mass, i guess a lot will change.
05:31
So i will have a 2 to 1.
05:38
I've got to go back down here...