Fructose is a common sugar found in fruit. Elemental analysis of fructose gives the following mass percent composition: C 40.00%, H 6.72%, O 53.28%. The molar mass of fructose is 180.16 g>mol. Find the molecular formula of fructose.

Video transcript

Hi everyone. So here we ask chocolate. The empirical molecular formula a beauty like acid. It has a molar mass of 88.11 g per mole In a mass percent composition of % 54.53 carbon 9.15% hydrogen And 36.32% oxygen. And we know that the empirical formula it's gonna give us our relatives number of atoms and then our molecular formula, it's going to give us our actual number of atoms. So we're gonna assume we have 100 g of the compound. We can convert our percentages into grams. We have 54 0.53 grams of carbon 9.15 grams of hydrogen in 36 0.32 friends of oxygen. So now we're going to convert the masses of each into moles. Using the molar masses in one mole of carbon, We have 12.011g of carbon And give us 4.54 malls of carbon In one mole of hydrogen. We have 1.008 brands of hydrogen. And this will give us 9.08 malls of hydrogen in one mall oxygen. We have 15 .999 grams of oxygen. And this will give us 2.27 malls of oxygen. Now we need to divide each by the smallest number of moles. Get the smallest whole number ratios for carbon. We have 4.54 By by 2.27. We're going to get to for hydrogen With 9. By about 2.27. We're gonna get four for oxygen. You have 2.27. About about 2.27. We're Gonna Get one. So now these are going to be our subscript and empirical formula. Our empirical formula is C. Two, age four. Oh. And now I need to find what number to multiply the subscript spy. To get the whole number ratios for the molecular formula. We can do this by using the equation X. It was a miller mass. What about the empirical mass? Our empirical mass Fc two H 40. Is too Times 12.011g. Last four 1.008g plus 15 .999 grams. We're gonna get 44 0.5 grams. So we have X. It was 88 1 1. About about 44 0.5. I'm gonna get to. And now we need the most part of subscript in the empirical formula by two UFC two H 40. We're gonna get c. four H eight tonight. For a molecular formula, We're gonna get c. four H. Eight 02. Thanks for watching my video and I hope it was helpful