# aamc chem question pack #23

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#### nostra_damus

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Can somebody explain this to me please? I'm still a little confused why the answer isn't A. Thanks!

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#### nostra_damus

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Sorry realized I cut off the question part

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#### aldol16

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What part don't you get? It's a stoichiometry problem - the only caveat is that instead of having A + B ---> AB, you have n as coefficients. So let's make it more concrete by picking numbers. We'll use 2 to keep it simple - so you're making a dimer. 2 CDP ---> (CP)2 + 2 HPO4. What's the ratio of polymer (the dimer in this case) to HPO4? Well, it's 1/2. You can keep repeating this exercise - with n = 3, you'll get 1/3; with n = 4, you'll get 1/4 and so on. So the ratio of polymer to HPO4 can be obtained by the ratio 1/n.

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#### Sharknad0

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What part don't you get? It's a stoichiometry problem - the only caveat is that instead of having A + B ---> AB, you have n as coefficients. So let's make it more concrete by picking numbers. We'll use 2 to keep it simple - so you're making a dimer. 2 CDP ---> (CP)2 + 2 HPO4. What's the ratio of polymer (the dimer in this case) to HPO4? Well, it's 1/2. You can keep repeating this exercise - with n = 3, you'll get 1/3; with n = 4, you'll get 1/4 and so on. So the ratio of polymer to HPO4 can be obtained by the ratio 1/n.

Is that because even though there's multiple subunits, it's just 1 mole?