Condensed Formula - Video Tutorials & Practice Problems
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1
concept
Condensed Formula
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Now Condensed Formula shows how the atoms in a compound are bonded without showing all the bonds. Now, carbon and hydrogen atoms are grouped together in blocks. So what I mean mean by that is we have CH 3, where the 3 hydrogens on the compounds are packed together, grouped together. C h 2, the 2 hydrogens on the carbon are grouped together, and then c h, the carbon and the hydrogen are grouped together. If we take a look here we have our structural formula. Here our structural formula shows all the bonds being created between our atoms. We're showing all the carbon carbon bonds, and all the carbon hydrogen bonds. Now, with condensed, we would package in this c h 3, so bring in those 3 hydrogens, and the reason we draw it backwards like this is to show that it's the carbons that are connecting to each other, and not hydrogen to carbon. Because if we wrote it this way, it would almost look like my 3 hydrogens are connecting to my carbon, but they're not. It's the carbons that are connected to each other. Here we have our CH2, so bring in those 2 hydrogens with the carbon, so we have CH2 here. And then here on the right end here we have CH 3 again, bring in those 3 hydrogens to give us CH 3. Now we can go even further and and condense it even more by erasing those bonds that show the carbon carbon linkages. So here I erase this bond and this bond, and just bring everything in closer, so my fully condensed formula would be CH3 CH2 CH3. So this is how we go from our structural formula to our condensed formula.
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example
Condensed Formula Example
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Here it says draw a condensed formula for a compound with the following molecular formula, c 4h10. Here we're given a hint, arrange all carbon atoms in a row. Alright. So we'd have our carbons all connected to each other, our 4 carbons, and remember carbon wants to make 4 bonds. And in order to do that, we distribute hydrogens to all of them. So this here represents my structural formula, where I'm showing each of the bonds between carbon carbon and carbon hydrogens. But remember, we want the condense so now we package things in. Here we have a carbon connected to 3 hydrogens, so that's CH3. Then we have carbon connected to 2 hydrogens, that's CH2. Again another CH2, and then finally we have a carbon connected to 3 hydrogens again, that'd be a CH3. So this will represent our Condensed Formula, CH3CH2CH2CH3. This would be our final answer.
3
concept
Parenthesis and Parenthesis w/ Subscripts
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In this video, we're gonna talk about condensed formulas, including parenthesis and parenthesis with subscripts. So here we're going to say that groups that are in parenthesis are branches, or branch structures. So example, we have CH 3 here. If we take a look at this structural formula, we see that we have these 3 carbons here in a row together. And branching off of that middle carbon is our CH three group. Now, if we change this structural formula into our condensed formula, we'd start out by saying, we have a CH three group here, which is shown here. That then comes after that a CH group right here. Branching off of that CH group is our CH 3 group up here. To designate it as a branched structure, we put it in parenthesis, and then we continue down our chain, after this CH is our CH3. So after this branched group here, branch structure, we write CH3. So as our molecules or compound become more and more complex, we're gonna sometimes need to utilize parenthesis to talk about the branched structures coming off of my main chain. Right? So this is just one way we can illustrate that this CH three in this particular structure represents a branched structure. Alright. So we're gonna start doing more and more complex ones, and we're gonna incorporate more and more parentheses.
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example
Condensed Formula Example
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Here it says write a condensed formula for the following compound. So here we have c h 3 connected to a c h, which contains a CL coming off of it, that CH is connected to another CH that has a BR coming off of it, and then we end with another CH 3. So how would we write this? Well, we're gonna have our CH 3 to start, that's connected to our CH group. Remember we use parenthesis to show our branches, that's CL as a branch, so we put parenthesis CL. Then we have another CH, which has its own branch of BR, so in parenthesis, and then we conclude it with our CH 3. So this will represent our condensed formula with our 2 branches of Chlorine and Bromine.
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concept
Condensed Formula with Subscript
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Our continued discussion of condensed formulas, now we take a look at parenthesis with subscripts. In this case, they indicate repeating units. So for example, CH2. If we take a look at the structural formula of this hydrocarbon, we have what? CH3CH2CH2CH3. If we wanna convert this to condensed, we learned that we could have done CH3, and then we could do CH 2, CH 2, and then CH 3. But we can further condense this even more. We're We're gonna say that these 2 c h twos in the middle, we can combine them even more. Putting them in parentheses, and then putting a little subscript at the bottom tells me that there are 2 CH twos in the middle of this hydrocarbon. So here, this would be another version of a condensed formula, where we have now repeating units.
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example
Condensed Formula Example
Video duration:
50s
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In this example question it says, draw a structure for the following condensed formula. Here we have c h 3, and then in parenthesis, c h 2, and then a subscript of 3, followed by c h 3 again. So here, we're going to say, we're starting out with c h 3, so we have a carbon connected to 3 hydrogens. It is now connected to 3 of these c h twos. So we're gonna have c h 2 here in the middle, another c h 2 here in the middle, and then finally our 3rd CH2 here in the middle. That last one is connected to the CH3 at the end. So this would represent our structural formula when given this condensed formula.
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Problem
Problem
Write a condensed formula for the given structure.
A
CH3CH(CH3)CH(NH2)CH3
B
C5H13N
C
CH3CH(CH2)CH3(NH2)CH3
D
(CH)2(CH3)3NH2
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Problem
Problem
Convert CH3(CH2)2CHBrCH3 into structural formula.
A
B
C
D
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