Many computer chips are manufactured from silicon, which occurs in nature as SiO₂. When SiO₂ is heated to melting, it reacts with solid carbon to form liquid silicon and carbon monoxide gas. In an industrial preparation of silicon, 155.8 kg of SiO₂ reacts with 78.3 kg of carbon to produce 66.1 kg of silicon. Determine the percent yield for the reaction.

Video transcript

Hey everyone, we're being asked to calculate the percent yield. If a 4.89 g sample of calcium oxide is reacted with excess water And 5.63 g of calcium hydroxide is actually produced. So before we move forward, let's go ahead and check if our chemical reaction is balanced. Looking at it thus far, everything is balanced. So we're good to go now we know that in order to calculate our percent yields, we're going to need our actual over our theoretical And we're going to multiply this by 100. Since we're looking for a percentage. Looking at our question, we see that they've given us our actual yield right here. So let's go ahead and calculate our theoretical yield. And we're going to do so by taking our 4.89 grams of calcium oxide. And we're going to look at our multiple ratios and determine this. Now, looking up calcium oxides molar mass or calculating it ourselves, We find that it's 56 g per one mole. And looking at our balanced chemical reaction, We can see that one mole of calcium oxide Is equivalent to one mole of calcium hydroxide. So we have a 1-1 ratio. Now we want to convert our moles of calcium hydroxide into grams. And we're going to do so by taking calcium hydroxide molar mass And we find that it's 74 g per mole. So when we calculate this out and cancel out our units, We end up with a value of 6.46 grams of calcium oxide. Now we're going to use this value and plug it into our equation. So our percent yield Is going to be our actual which is 5.63 g of calcium oxide. Over our theoretical yield of 6.46, which we just calculated. And we're going to multiply this by 100 and this is going to get us to a percent yield of 87.1%. So looking at our answer choices, it looks like B is going to be our final answer. So I hope this made sense and let us know if you have any questions.