Solution Stoichiometry Example 1

Jules Bruno
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in this example question. It says how many moles of hydrogen gas were produced when 38.74 mL off 0.275 more water reacts with excess sodium? All right, so we know that this is a balanced chemical equation. They're giving us information on one compound and asking for information on another. So this is the definition of stock geometry, balanced chemical equation. They give us information on at least one compound, and when you start geometry to find the other now here we're gonna follow the steps to deal with this solution. Start geometric question for step one, it says, to convert the given quantity into moles of given. Now, if a compound is said to be in excess, then just ignore it. So here they're telling us that sodium is an excess sodium doesn't matter. Here. Now, up above, I said that moles equals leaders times more clarity. So we have to convert our millimeters here into leaders. So we have 38.74 mL and we're going to stay here for everyone. Millie, it's 10 to the negative three leaders. Now that we have leaders, the next thing we can say is that polarity, remember, represents a conversion factor. So that 0.275 Moeller of water really means we have 0.275 moles off water for one leader of solution. So at this point, we've just isolated are moles of Given Now, Step two says we're gonna do a mole to mole comparison to convert the given into moles of unknown. So at this point, remember when we do a multiple comparison, we look at the coefficients in the balance equation, and it's two moles of water for every one mole off H two, which is what we're looking for. So then moles of water down here, Moles of H two here. At this point, we're done because they're only asking us to find the moles of hydrogen gas. But let's just look at the other steps, if necessary, convert the moles of unknown into the final desired mole units. So here, the only one that moles of H to weaken stop. But if they wanted us to go to grams, we have to go a little bit further if they wanted us to find molecules to go a little bit further. Now Step four. If you calculate mawr than one final amount, then you must compare them to determinate theoretical yield. The smaller amount will equal your limiting re agent. So the reaction that makes less product will be the limiting regent. The one that says it can make Mawr product will be the excess regent. In this question. We don't have to worry about Step three because we only needed moles. And we don't have to worry about Step four because only one compound how to giving them out. So we're going to do here is we're gonna plug this into our calculator, and when we do, we get 5.33 times 10 to the minus three moles of H two as our final product for this story, you metric solution type of.