CHEM 1405 Concept Review: Aldehydes, Ketones, & Oxidation Reactions
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Aldehydes Vs. Ketones
| Type of Compound | Aldehyde | Ketone |
| Special Characteristic |
A carbon at the end of the chain (either the first or last carbon) is double-bonded to an oxygen |
A carbon in the middle of the chain is double-bonded to an oxygen |
| Example |
(Propanal) |
(2-pentanone) |
| Naming Scheme | Name the compound according to the longest carbon chain containing the C=O, but change the ending to “-al”. No number is needed to identify the location since the aldehyde group ( |
Name the compound according to the longest carbon chain containing the C=O. Like alcohols, indicate the number of the carbon containing the Ketone group ( Note: Ketones only require a number indicating the location of the ketone group if the ketone has 5 or more carbons in its longest chain. |
Oxidation Reactions
Alcohols:
|
Primary Alcohols |
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Secondary Alcohols |
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Thiols:
Aldehydes:
Chirality
Chiral: A descriptive word describing an object that is non-superimposable with its mirror image. It can also be thought of as “handedness”, as the left hand is not superimposable with the right, yet they are mirror images of one another. These objects are asymmetric (having no plane of symmetry).
Achiral: A descriptive word describing an object that is superimposable with its mirror image. Such objects have an internal plane of symmetry. This causes the mirror image to be identical to the original object.
Chiral carbons: Specific carbons are considered chiral if they are bound to 4 different groups. A chiral carbon usually causes the entire molecule to be chiral.
Enantiomers: Molecules that are mirror images of one another, but not superimposable and therefore different compounds.
Fischer Projections
Fischer projections are a way of drawing molecules that helps to represent the 3-dimensional characteristics of a molecule. A Fischer projection takes the position of looking at a molecule in such a way that the top and bottom atoms or groups are bent away from you and the horizontal groups are bent toward you. An image of what this looks like is as follows: