00:02
Hi there.
00:02
In this question, we are given a mass of hydrogen as 5 .71 grams, and we want to determine how many grams of nitrogen are necessary to react with that.
00:13
Therefore, this is a mass to mass stoichiometry problem, where we have the mass of one thing in the equation, and we're trying to determine the mass of another substance.
00:26
Okay, so let's plan this out.
00:29
If we have a mass of hydrogen, the first thing we need to do is to convert that to moles of hydrogen.
00:36
And we'll do that by using the molar mass of hydrogen.
00:42
Then we can use the mole ratio from the balanced equation to convert to moles of nitrogen.
00:49
So we want to use that mole ratio.
00:51
And the mole ratio comes from the coefficients in the balanced equation.
00:55
They show us that for every three moles of hydrogen, we need one mole of nitrogen.
01:03
Since there's no coefficient written for nitrogen, it's understood that it's a one.
01:09
All right.
01:10
So we'll use that mole ratio.
01:11
And then finally, we'll convert from moles to grams of nitrogen by using its molar mass.
01:18
Okay, so let's go ahead and set this up and see which of those conversion factors we're going to use.
01:24
So we're starting with 5 .71 grams of hydrogen.
01:28
And we need the molar mass of hydrogen.
01:31
But we need to put the grams of hydrogen in the denominator so that those will cancel and one mole of hydrogen in the numerator.
01:39
So we need one mole of hydrogen over 2 .016 grams of the hydrogen...