A model of an alkane appears in the window below. ball ...

A model of an alkane appears in the window below. ball & stick - + labels Which of the following have the same molecular formula as the molecule shown in the model? Choose all that apply. CH2-CH3 CH3-CH2-C-CH2-CH3 CH3 CH3 CH3-CH2-CH2-CH-CH2-CH2-CH3 CH3 CH3-CH-CH2-CH2-CH3 CH3 CH3 CH3-CH-CH2-CH-CH3

Transcript

00:03 Hi there.

00:03 In this question, we are given the ball and stick model of an alkan.

00:10 And the term alkan, of course, means a hydrocarbon containing all single bonds.

00:32 And all non -cyclic alkanes have the same chemical formula.

00:36 That is going to be c to the n, h to the 2n, plus 2.

00:43 So as we look at the model that we have here, we count up that it has eight carbons.

00:50 For its chemical formula is c8, and we don't even have to count the hydrogens.

00:56 You can if you want to, but two times eight is 16 plus two is 18.

01:02 So c8, h -18.

01:06 And we want to know which of the following, which of those ones listed there, are going to have the same molecular formula as the molecule shown.

01:16 All of these options, i'm just going to label them, a, b, c, and d, so that it's easier to talk about them.

01:24 All of these options here have single bonds.

01:27 So they are all alkanes as well.

01:30 So they're all going to have that same formula.

01:33 C to the n, h to the 2n plus 2.

01:38 So to determine which ones have the same molecular formula, we just need to count up the carbons.

01:45 In the first one, counting the carbons gives us a chain of 5, 1, 2, 3, 4, 5.

01:52 Then we have an ethyl group.

01:54 Adding two more and a methyl group for a total of eight carbons.

01:59 So that's c8 and then its general formula h to the 2n plus 2 means it must have 18 hydrogens because everything is single bonded there...

Question

A model of an alkane appears in the window below. ball & stick - + labels Which of the following have the same molecular formula as the molecule shown in the model? Choose all that apply. CH2-CH3 CH3-CH2-C-CH2-CH3 CH3 CH3 CH3-CH2-CH2-CH-CH2-CH2-CH3 CH3 CH3-CH-CH2-CH2-CH3 CH3 CH3 CH3-CH-CH2-CH-CH3

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