So as we said, we're given 12.3 grams of H2 and asked to find how many grams of H2O would form. The way we're able to do this is through stoichiometry. And to find how many grams, we'd use the stoichiometric chart. Now the chart uses the given quantity of a compound to determine the unknown quantity of another compound. The way it works is we're starting here on the left side and on the left side, the information they give to us is called the given information. Now, this information that's given to us can be presented as grams, and if it's presented as grams, then we can just do a conversion to get to moles. So, we can go from grams of given to moles of given. Now, besides giving it to us in grams, it could be given to us in ions, atoms, formula units, or molecules of given. Again, we're heading towards moles of given. So our basic movement is going from the left side of the chart toward the right side of the chart to our unknown information.
Now that we have our moles of given, we have to basically take a jump, a leap of faith from an area where we know information because it's given to us, to an area where we know nothing at all, so it's unknown to us. And this jump or leap of faith that we're going to take, we call it the jump. To be able to do this jump, you have to do a mole to mole comparison. And in a mole to mole comparison, use the coefficients in the balanced equation. That's why it's incredibly important you first have a balanced equation before you even attempt to do stoichiometry. Once we've gone from moles of given to moles of unknown, and then we can either stop there if they want us to find the answer in moles, or continue onward to ions, atoms, formula units, or molecules of unknown or to grams of unknown. In this case, from the example that we have up above of our equation, we would say that this is the grams given to us, so this would be our grams of given.
We would have to basically take the trip of grams of given to moles of given to moles of our unknown, our unknown is what we're looking for which would be water, and then we'd have to stop here at grams of unknown. That's the path we have to take. We utilize the stoichiometric chart to help us answer any type of stoichiometric question. Now that we've seen this chart, move on to our example question and let's put it to work, put it to practice in terms of this stoichiometric chart.