-- Isomers can be broken down into constitutional isomers and stereoisomers

-- Stereoisomers can be broken down further into enantiomers and diastereomers

-- Isomers = different compounds with the same molecular formula

-- Constitutional isomers = same formula, different connections

-- Enantiomers = mirror images

-- Diastereomers = some but not all chiral centers change

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Find the index of hydrogen deficiency for the following:

Formula for index of hydrogen deficiency:

X is the number of carbons.

Y is the number of hydrogens.

Count the carbons:

There are eight carbons.

Now count the hydrogens:

There are eight hydrogens.

Plug these values into the formula.

The IHD is 5.

This makes sense because you can count rings and double bonds.

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