3.1a Organic Molecules Flashcards
Unit 3: Organic Chemistry & Instrumental Analysis
What are 3 rules when naming organic compounds?
-Find the longest carbon chain to give the name stem
-Number the position of any functional group
-Add the name and number of any branches in alphabetical order
What is a Haloalkane?
These are substituted alkanes in which one or more of the hydrogen atoms is replaced with a halogen atom (e.g 1 Bromopropane)
What is a Monohaloalkane?
One hydrogen has been replaced with one halogen atom
What are Ethers?
These are substituted alkanes in which a hydrogen atom is replaced by an alkoxy functional group: -OR where the R represents an alkyl group
How are Ethers named?
-the longest C chain is found - this is the name stem
-add “oxy” to the attached alkyl group
(e.g methoxylpropane)
How does ethers bonding effect their boiling points?
There C-O bonds are weakly polar, this has very little effect on their boiling points, so they are low.
However as the Carbon chain increases their boiling points increases due to LDF
How does ethers bonding effect their solubility?
Ethers containing up to 3 carbon atoms are water soluble as they can contain an H-bond with water, due to the non bonding pair of electrons on the oxygen atom. As the C-chain increases they become less soluble in non-polar solvents as the hydrocarbon chain dominates the molecule
What is the function ethers?
They are used as solvents due to their inherit behavior, and ability to dissolve many organic compounds
What is meant by aromatic?
This is a term used to describe an organic molecule that contains a benzene ring. (Benzene is the simplest aromatic molecule)
Why is benzene stable?
Benzene has a distinct structure that makes it very stable, due to its conjugated system and its delocalised electrons. The carbon bonds that are joined by bonds are equal, not a single-double bond structure
What is a conjugated system?
Alternative single and double bonds
What is the prefix used when the substituted benzene ring is attached to another formula?
It becomes a phenyl and has the formula C6H5
What are Amines?
Amines are organic derivatives of ammonia, in which one or more of the hydrogen atoms of the ammonia are replaced by an alkyl group (R)
How do you know if an amine is primary, secondary or tertiary?
It depends on the amount of R groups attached
1 R group (2 hydrogen atoms) = Primary
2 R groups (1 hydrogen atom) = Secondary
3 R groups (no hydrogen atoms) = Tertiary
Which amines show hydrogen bonding?
Primary and secondary amines due to their N-H bonds
How does amines hydrogen bonding effect their boiling points?
The boiling points of primary and secondary amines are higher as they show hydrogen bonding and tertiary does not
Are amines water soluble?
The H-bonding of the smaller chain amines allows interactions with water making them soluble. The non-bonding pair of electrons on the tertiary amines gives increased polarity to the molecules allowing them to interact with the water molecules. As an alkyl chain length increases water solubility decreases
Are amines acids or bases and what does this mean?
They are weak bases and will dissociate slightly in aqueous solutions. The lone pair of electrons on the nitrogen in the amine molecule accepts a proton from the water molecule forming a positive alkylammonium ions and negative hydroxide ions
What are amides?
They are carboxylic acid derivatives in which the -OH of the carboxylic acid has been replaced by the -NH2, -NHR OR NR2 of an amine
What are nitriles?
These are organic compounds with a cyano group attached to the terminal carbon R-C—N (— means triple bond)
What are carboxylic acids?
These have a carboxyl group on the terminal carbon atom, the hydrogen on the carboxyl group dissociates allowing the molecule to behave as a typical acid in its reactions. They are weak acids so exist in equilibrium between the molecular and ionic form
What can carboxylic acids react with to form salts
-metal hydroxide
-metal oxide
-carbonate
-ammonia
What is produced when a carboxylic acid reacts with an amine?
The product is an alkylammonium salt
What happens to alkylammonium salts when they are heated?
The alkylammonium salt can be heated to form the corresponding amide with the loss of a molecule of water.
How are esters formed?
They are formed from the condensation reaction between an alcohol and a carboxylic acid or acid chloride
How are esters formed using carboxylic acids?
The alcohol and acid mixture is heated under reflux with a catalyst of concentrated sulfuric or phosphoric acid (this method does not work with phenol alcohols)
What are acid chlorides?
An acid chloride is a molecule in which the hydroxyl group of an acid is replaced by a chlorine atom
How are esters formed using acid chlorides?
When using an acid chloride instead of the acid, the reaction is much faster and a catalyst is not required. It will proceed at room temperature, and works for the production of esters containing phenols
