00:03
Hi there.
00:04
In this question, we are given the mass of the reactant, and we want to know how many grams of one of the products can be formed from that.
00:12
So that means this is a mass to mass stoichiometry problem.
00:19
And for any stoichiometry problem, we need a balanced chemical equation because that's where we get our mole ratio.
00:27
Well, we are given a balanced chemical equation here.
00:30
It is 2h2.
00:33
Decomposes to form 2h2.
00:38
Plus o2.
00:39
And i've left the states of matter out because the states of matter are not necessary for stroke geometry.
00:45
Okay, so i mentioned something about the mole ratio.
00:49
So this is showing us that for every two moles, so the coefficients are showing us the mole ratio.
00:54
For every two moles of h2, we will produce two moles of h2 and one mole of o2.
01:00
If there's no coefficient written in front of a substance, it's understood that it's a one.
01:06
All right, so in this question, we are starting with seven and we want to know how many grams of h2o.
01:14
And we want to know how many grams of o2 we can produce.
01:20
All right, well, let's plan out our steps.
01:22
If you recall, i said that for stokeometry, we need that mole ratio.
01:26
But right now, our reactant is in grams.
01:30
So we need to convert that to moles of h2o by using h2o's molar mass.
01:38
And we get the molar mass by adding together the mass of each of the elements in the compound.
01:42
So two hydrogens and one oxygen...