The molecular formula of a compound having an empirical formula n...

Question

The molecular formula of a compound having an empirical formula nh2

Accepted Answer

Alright, so in this practice problem, we are given a compound, we have its molecular weight in atomic mass units 358.30 atomic atomic mass units. We need to identify the molecular formula for this compound given the empirical formula. So we want molecular formula but we already have empirical formula of that. So that's going to be really easy to do. All right, So the molecular weight that's given to us is actually the molecular weight of the molecular formula. Okay, what we need to do is actually calculate the molecular weight of the empirical formula to see how many empirical formulas could fit into the molecular formula. Okay, so let's go ahead and do that. So, atomic mass units here is going to be the same thing as grams per mole. And we'll be able to find the molar masses of each of these elements on the product table. So for CH two H 20. We're going to have the molar mass of Carbon. Carbon is 12.1 Hydrogen. We have two hydrogen times its smaller mass, which is 1.01. And then for oxygen there's only one and it's about 16 g or am you units. Now let's go ahead and add that together. So that will be 2.02 for hydrogen. Once we add that together, we get to 30 point oh three atomic mass units. Okay, so now we're going to go ahead and take the molecular weight and then divided by the empirical weight. Okay, so 3 8.30 I am U units divided by 3003 Atomic mass units. And of course that will cancel out just going to give us a ratio and that number will be 19.9. We're going to round it up to 12. Okay. Which means that there's actually 12 of these of empirical formulas within the molecular formula. Because remember, empirical formula is going to be the simplest whole number ratios But that's not necessarily what the molecular formula, what the actual compound looks like. So we need to take the molecular formula and multiply it by 12. And that will give us the molecular formula. It's a molecular formula is going to equal to CH 20 times 12. Alright, so we're gonna multiply all of the elements by 12. So carbon by 12, that's going to give us 12 carbons to hydrogen is by 12. That's going to give us 24 hydrogen and then oxygen times 12. There will be 12 oxygen's right. So that is the new formula. And that is going to be the molecular formula of this compound. And that's it folks. Thanks so much for watching

The molecular formula of a compound having an empirical formula nh2

Watch next