How many hydrogen atoms are needed to complete the hydrocarbon formulas for the following carbon backbones?
b.

Question

How many hydrogen atoms are needed to complete the hydrocarbon formulas for the following carbon backbones?

b.

Accepted Answer

All right. Hi, everyone. So this question is asking us how many hydrogen atoms are required in each of the given carbon backbones to complete their hydrocarbon formulas. And here we have two or sorry, three different models. So just to give a little bit of context here, right, recall that organic compounds are characterized by having a carbon backbone in which multiple carbon atoms connect together in various ways to create the diverse structure that we see in organic compounds. And the reason why these kinds of intricate structures are able to form is because of carbon's et cetra valence, right, because carbon has four valence electrons in the outermost shell carbon is therefore able to create four covalent bonds, whether it be with other carbon atoms with hydrogen or other atoms such as oxygen, nitrogen, et cetera, these four covalent bonds help carbon maintain its octet all eight valence electrons that carbon needs. So when it comes to the given carbon backbones that we're seeing here, the idea is to find how many electrons are missing from carbon octet. So here when it comes to finding the number of hydrogens that each carbon is going to need the idea is to subtract the number of bonds it already has with other carbons from four, right. So four subtracted by the number of bonds a given carbon has with other carbon atoms should give you the number of bonds missing. And that corresponds to the number of hydrogens that carbon needs to complete its octet. For example, right, if we focus our attention on model one here, oops accidentally move this too much. But if we consider the first model here, right, the first carbon atom in green on the very left side of the structure only has one bond, two, another carbon atom. So we would subtract the one bond from the four that carbon requires. That means that means the three bonds are missing. Therefore, three hydrogens are needed on that carbon to satisfy its octet. So to add up the total number of carbons, I'm going to start with the three from the carbon on the very left side before continuing on to the carbon atom right next to it. Now, the second carbon here has two bonds to other carbon. So that's four, subtracted by two means that two bonds are missing and therefore two hydrogens are required for that carbon. And now I can proceed to the next one. Right now, the next one has three bonds to three different carbon atoms, which means that one hydrogen is missing or it. And as we can see on the very right side of the structure are two carbon atoms that have one bond each to the same carbon atom. So both of those are going to need three hydrogens to complete its octet. And so when I add everything together, I get 12 hydrogens needed to complete the hydrocarbon formula. So now we can proceed with the next one or the second mo Now, what I want to point out here is that if we consider the two carpet on the very left side of the second model, there's a double bond between them instead of a single bond. So even though its only one double wand, it would count as two bonds, right? So if I consider the carbon here, the green circle to the very left side of the second model, I would subtract four from the two bonds of the double bond itself that gives me two, which indicates that two hydrogens are needed to complete its octet. And so the carbon right next to it has two bonds from the double bond as well as one more from the single bond on the right side of it. So four subtracted by three in total means that one more hydrogen is needed for that carbon. And so the next one over has three single bonds to different carbons, which means that it has three bonds in total. Therefore, four subtracted by three, gives me one and once more, I have two other carbon atoms on the right side that are each connected to only one other carbon atom. So both of them are going to require three hydrogens. So when I add everything together, I get 10 hydrogens to complete the second hydrocarbon formula. And last but not least I can proceed with the third model. Now, the third model has a triple bond in between two carbons. So the triple bond is going to count as three bonds as well. Though, if I consider the first carbon on the left side of the third model, I would subtract three bonds from the triple bond from the four needed or carbon. So four subtracted by three equals one. Therefore, one hydrogen is needed to satisfy the octet of the carbon farthest to the left in the third structure. And the second one, the second carbon of the triple wand, that one actually has all four bonds because notice how we've got three from the triple wand and one more to the right of it. So that's four subtracted by four equals zero. Meaning that zero hydrogens are necessary to satisfy the octet of that particular car. For the next one over, we have three bonds to other carbon atoms. Therefore, one of hydrogen is needed to complete the one bond that's missing. Now, on top of or above the carbon that we just reviewed is another one that only has one bond to another carbon. Therefore, three more hydrogens are needed. But to the right of it, we've got one that has two bonds to other carbons. Therefore, two hydrogens are necessary until the very last carbon down below here is missing three hydrogens as well or is missing three hydrogens. And when I add all together I get 10 and there you have it, here are the number of hydrogen atoms required to give each carbon backbone, their complete hydrocarbon formula, right? For part one, it was 12, for part two, it was 10 and for part three, it was also 10. So with that being said, thank you so very much for watching and I hope you found this helpful.

How many hydrogen atoms are needed to complete the hydrocarbon formulas for the following carbon backbones?
b. <IMAGE>

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