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Problem 28

Calculate the percentage of carbon by mass in each of the compounds represented by the following models:

a) 27.3$\%$
b) 37.5$\%$
c) 79.88$\%$
d) 15.8$\%$

## Discussion

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## Video Transcript

in this problem were provided with some model ofsome compounds. And we have to find out on the percentages of carbon My mama's in. Those come bars were presented by the models. So first you have to know the formula for finding out the mass person does off a specific element which is present in a compound. And the formal of for doing that is this where the mass percentages often element is equal to the number of that element present in the compound times the atomic weight off the specific element over the formal await off that compound times hundred person. So our first model here is thiss where this black as fair is carbon and is a race fiercer oxygen. So from here, our formal of the compound is here, too. And that made a formal of weight of this compound will be simply the sum of the squares off each at present. So we have one Carbone that Ms Carbons that we quit is syrup on our no, it's twelve point zero one at wig mus unit blast We have to rock season and oxygen settlement what is sixteen and he multiplied by two and will give us a value off forty four point zero one zero seven. Admit Miss Unit. And then you can find the percentage of carbon in Seo too, by his putting atomic weight off carbon. Since we have only one carbon, we don't have to put on the number of carbon present. Her prints were all over the formal away, which is forty four point zero one zero seven and multiplied by one hundred percent. Give us a value off. I'm going to seven point two nine percent. So this is the person turns off carbon in carbon dioxide are dumb model given here. Then he moved to the next problem. Where are this again? This on blacks various carbon and this wreck for his oxygen. And are white sphere so high treason. So we have rhymed forehead risen present Three of them are bound tto carbon that Mrs Ch three and then oxygen And then ah, the rest of the hydrogen is bound with that oxygen. That means this is an oid age and this resume uch three. So seeing three wages the formal of the compound And if we find out the formal of weight of thiss we have one carbon were parent zero one. So I'm not writing here that that would mess in it every time. But while writing in the exams, you should have written that unit very carefully and write down. Will present on M u r for oxygen. All the atomic weight should represent it in am your every mess unit. All right, so that was a weight of Communist Welburn No. One. Plus we have four hydrogen on head prisons. Atomic weight is one point zero zero eight. We're four high treason. Multiply it by four and then we have on oxygen, which is sixteen point zero. And it will give us a total Hello off thirty two point zero four entirely too burned, zero for three and a mule. So this is the formal await of this. And then the percent ofthe carbon here will be so we have only one carbon here again. Just put the atomic weight of carbon over the formal await started a burned zero for three times one hundred percent give a savella off thirty seven point four eight percent. So this is the percentage of carbon in C Street Oyj or which is the formal over the middle, Then we moved. Or next problem here we can see that we have two carbons and three hydrogen bound. Which carbon? That is the formal siege three ch Dream Oregon. Write it as C two h six. So the formal away for this component was simply to carbon. We have open. So on times two plus we have six head Rosen, one point zero zero eight is the atomic weight of hydrogen times we have six had risen and the total relievers thirty point zero six nine four at McManus unit. And make sure you write am You've after every anthemic way to write that Mr Weapon on emu and one point oh eight emu and then the person off carbon will be equal to Says he took urban This time we'LL put it to hear times twelve apartment or one I am you over this formula weight which is thirty point zero six nine for a mu multiplied by one hundred percent when he was seventy nine point eight percent. So this is the mass percentage ofthe carbon in situate six and finally we have this formula where we can look, eh one carbon in the media. Since The blue one is nitrous and we have two night risen and we have one sell for and they have four hide risen, which are white ones. So the formal weaken right is ch for into this This is the formula off the compound. What is represented by this model and formal away for this will be called us for carbon. We have to a point zero one plus we have forehead Rosen and find President said iniquitous serum one point zero zero eight times four plus night Rosen's and a big weight is fourteen point zero zero six seven. We have two night risen and everyone self far, which is thirty two point zero six five caregivers formula waiters seventy six point one to one Patrick Mus unit and then the percent ofthe Carbone bam! Still, we have only one carbon in this one too. So well planned zero on Amy. Oh, over that time, equate are the formula weight of the compound, which is seventy six point one to one times hundred person until you give us fifteen point so and so on person. So this is them. Ah, mass person is off carbon in the compound presented here