Mod+4+Reading+Guide

__**Reading Guide for Module 4**__ The main point of Module 4 is to be able to identify, name, describe, and draw compounds with functional groups that include oxygen atoms such as alcohols, ethers, carbonyls, and others while beginning to identify, name, and draw chiral molecules.

__13.1: Alcohols, Phenols, and Thiols__ ->Summary: Alcohols are compounds with an OH functional group, phenols are alcohols connected to a benzene ring, and thiols are compounds with a SH functional group. Alcohols can be named as primary, secondary, or tertiary based on how many carbon atoms the functional group's carbon is attached to. For example a primary alcohol is connected to a carbon that is connected to only one other carbon, a secondary alcohol is connected to a carbon that is connected to two other carbon atoms, and a tertiary alcohol is connected to a carbon that is connected to three other carbon atoms. Alcohols are named by replacing the -e on the end of the alkane with an -ol, they are numbered starting with the side closest to the OH group, and substituents are numbered starting with the side closest to the alcohol. Phenol compounds are named with the suffix phenol much like the suffix benzene is used for aromatic compounds, their carbon atoms are always numbered starting with the carbon attached to the OH group, and substituents may be named using ortho (1,2), meta (1,3), and para (1,4) or numbers for the carbon atoms. Thiol compounds are named by adding thiol to the end of the alkane and numbering substituents and SH groups starting with the side closest to the SH group.

->Struggling Topic 1: Which common names for alcohols, phenols, and thiols should we be expected to know? None are listed under the objectives, but some may be like toluene was in the aromatic compounds.

->Struggling Topic 2: Is the carbon in methanol considered primary, secondary, tertiary, or none of these? I would assume it is none of these since the carbon is attached to no other carbons.

__13.2: Ethers__ -> Summary: Ethers are compounds with oxygen atoms attached to two carbon groups that are alkyls or aromatic rings. Ethers are named by writing the name of each alkyl or aromatic group attached to the oxygen atom in alphabetical order followed by the word ether. Cyclic ethers contain an oxygen atom in a carbon ring, and these rings are heterocyclic because they have rings with atoms other than carbon. Cyclic ethers are often given common names like furan (a four carbon, 1 oxygen atom ring). Cyclic ethers are numbered beginning with the oxygen atom. Dioxane is a cyclic ether with two oxygen atoms and 4 carbon atoms, and the oxygen atoms are numbered starting with one of the oxygen atoms. Alcohols and ethers are sometimes isomers because they have the same composition but different connectivity.

->Struggling Topic 1: Which cyclic ether common names should we know for our quizzes? None are listed as objectives, but our book seems to suggest that furan and dioxane could be common names we should know.

->Struggling Topic 2: When are numbers in IUPAC names for ethers unnecessary? On the homework problems I missed methoxyethane didn't need a number 1, but 1-methoxypropane did need a number 1. Is this because the ethane group could only be connected one way/it could be rotated, but the compound would be identical? This would lead me to assume that the vast majority of the time there will be a # in the IUPAC name for an ether.

__13.3: Alcohols, Phenols, and Ethers physical properties__ -> Summary: Alcohols can hydrogen bond with each other, and ethers can hydrogen bond with water. Alcohols have higher boiling points than ethers and alkanes of similar size because of their hydrogen bonding. Alcohols with 4 or less carbons are very soluble in water, and those with 5 or more carbons are not very water soluble. Ethers are more water soluble than alkanes but less water soluble than alcohols. Phenols are soluble in water because the OH group ionizes like a weak acid.

-> Struggling Topic 1: The literature never specifically explained how phenol compares to hexanol. From the sound of it, hexanol must be insoluble in water because it has more than 4 carbons. Does this suggest that cyclic alcohols would have higher boiling points than non-cyclic alcohols? This would seem consistent with alkanes and cyclic alakanes.

-> Struggling Topic 2: Does the relative location of the oxygen atom make a significant impact on the solubility or boiling point of an alcohol or ether? It would seem reasonable that an alcohol or ether with a more accessible oxygen atom is more likely to be water soluble and have a higher boiling point than one with a less accessible oxygen atom. This seems to explain why alcohols in general have higher boiling points and water solubility than ethers.

__14.1: Aldehydes and Ketones__ -> Summary: An aldehyde is a carbonyl group that is bonded to at least one hydrogen atom (CHO - it isn't written COH because it would be confused with hydroxide), and a ketone is a carbonyl group that is bonded to two carbon atoms (CO bonded to an alkyl group or aromatic ring). When you name aldehydes, the e of the alkane name is replaced with -al, and the CHO never needs a number because it always appears at the end of the carbon chain. Numbering substituents always begins with the carbon in the CHO group. When you name ketones, you must be aware of both the common and IUPAC names. For example, acetone (propanone or dimethyl ketone) has three good names. In IUPAC naming, ketones are named by replacing the e in the alkane name with -one, and the chain is numbered beginning with the end closest to the CO (which has a number that goes in front of the alkone name). Then you name and number any substituents in the chain.

->Struggling Topic 1: Can benzaldehydes be named with o, m, or p the way benzenes and phenols can? For example, instead of 4-chlorobenzaldehyde, could you write p-chlorobenzaldehyde since the aldehyde will be assumed to be on the 1st carbon atom anyway?

->Struggling Topic 2: Which aldehydes and ketones have common names that we should know for our quizzes? Acetal aldehyde and acetone were both used in our book and in our homework questions. Are there other molecules like these whose common names don't expressly state the compound's composition that we should be familiar with? There is an objective stating that we should be familiar with common names of simple aldehydes and ketones. Which of these are considered simple?

__14.2: Properties of Aldehydes and Ketones__ -> Summary: At room temperature, aldehydes with 1-2 carbons are gasses, 3-10 carbons are liquids, and more than 10 carbons are solids. Aldehydes and ketones have higher boiling points than alkanes and ethers of similar masses because of dipole-dipole interactions. Aldehydes and ketones cannot hydrogen bond with themselves like alcohols can, thus alcohols have higher boiling points than aldehydes and ketones. Small carbonyl compounds (1-4 carbons) are very soluble in water, but carbonyl compounds with 5 or more carbons are not very soluble in water. The carbonyl group is able to hydrogen bond with water molecules.

-> Struggling Topic 1: Why can't an aldehyde hydrogen bond with itself? Is this because the hydrogen atom is bonded to the carbon atom, and it therefore doesn't have a slight positive charge? Whereas in an alcohol, the hydrogen is bonded to an oxygen atom and it causes the oxygen atom to have a slight negative charge and the hydrogen atom to have a slight positive charge.

-> Struggling Topic 2: Why does the difference between 4 and 5 carbons in carbonyl compounds so significantly change the solubility of the compound? I would have guessed that there would be a few carbonyl compounds that are very soluble, then some that are moderately soluble, and finally some that are insoluble.

__14.5:Chiral Molecules__ -> Summary: Structural isomers have the same molecular formula but different bonding arrangements. Stereoisomers have identical molecular formulas with the same connectivity but differ in how the molecule is arranged in space. Chiral objects are nonsuperimposable mirror images like a pair of shoes or hands. When one mirror image can be superimposed on the other, the object is achiral. Carbon atoms are chiral if they are bonded to four different atoms or groups of atoms. Enantiomers are stereoisomers that cannot be superimposed on each other. Fischer projections are ways to represent chiral molecules. They are always written vertically with the most oxidized carbon atom in the carbon chain closest to the top. These projections make it easier to see the chiral carbon and to identify the L (OH group on the left) and D (OH group on the right) versions of the compound.

-> Struggling Topic 1: Can a carbon atom that is part of a double or triple bond be chiral? I would assume that it cannot since alkene carbons become trigonal planar and akyne carbons become linear, and 2D compounds are easily flipped and superimposed.

-> Struggling Topic 2: How do you identify a chiral molecule as L or D if the compound does not include an OH group? Does the OH group simply refer to a B-L base? You could pick the more basic of the two atoms attached to the chiral carbon and identify the more basic one as L if it is on the left and D if it is on the right. Is this what happens in there is a chiral molecule without any OH groups?

__Critiques of this module:__ --A. How clearly the author communicated individual topics --->13.1 and 13.2 - the step by step directions for naming the alcohols, ethers, and other compounds is very helpful. Examples like these are much easier to understand than reading paragraph and sentence instructions. --->14.2 - the chart that displays the relative boiling points of alkanes, ethers, aldehydes, ketones, and alcohols does a good job illustrating the effect of different oxygen atom groups on the boiling point of similarly sized compounds.

--B. Specifics about the amount of content (did you need more examples?) --->13.3 - the examples of similar alkanes, ethers, and alcohols along with their boiling points and solubility was helpful in understanding the trends of these functional groups and their effects on the molecules as a whole. --->13.2 - the directions for naming the IUPAC names was much more clear than the directions for naming the common names. It would be easier if there were step-by-step instructions for the common names as well as for the IUPAC names.

--C. Chapter's place in the overall text --->13.2 - it is good that we have discussed isomers before Ch 13 because it allows the author to quickly discuss how it is common to have ethers that are isomers of alcohols.