Unit 2- Organic Chemistry Flashcards
What is Organic Chemistry?
- Organic chemistry is the study of carbon compounds and their properties
- Carbon’s structure allows in to make four strong covalent bonds
- Carbon can form single, double or triple bonds with other atoms and readily bond with itse
Why is Organic Chemistry Important?
- Organic chemistry is important because it is the study of life and all chemical reactions related to life
- Organic compounds are important sources of fuel plastics and medicines
Explain the difference between saturated and unsaturated hydrocarbons.
- Saturated hydrocarbons: Contain only single covalent bonds between carbons. Each carbon in the chain is bonded to the maximum number of hydrogens while still being part of the carbon chain. Saturated hydrocarbons have a straightforward zig zag in their structure.
- Unsaturated hydrocarbons: Contain one or more double or triple bonds between carbons, meaning there are less hydrogen atoms than their would be in a saturated hydrocarbon. Unsaturated hydrocarbons have kinks in their structure due to the double or triple bonds.
How do you name a straight chained alkane?
Write the following:
- Prefix: where the substitutions are located
- Root: How many carbons are in the molecules longest chain
- Suffix: Family- type of functional group (alkane, alkene, alkyne, alcohol, ester, etc…)
What are the prefixes for numbering carbon chains?
-1: meth-
-2: eth-
-3: prop-
-4: but-
-5: pent-
-6: hex-
-7: hept-
-8: oct-
-9: non-
-10: dec-
How are ringed alkanes named?
- A cycloalkane is a hydrocarbon in which the singly bonded carbon atoms form a closed ring. The general formula is CnH2n.
- To name add prefix cyclo
What are the 8 common Alkyl groups?
- methyl group
- ethyl group
- propyl group
- isopropyl group
- butyl group
- s-butyl group
- isobutyl group
- t-butyl group
Draw and name the 8 common alkyl groups.
*Check notes for answer
What is an alkyl group?
An alkyl group is a carbon branch attached to the main structure of the molecule.
How are branched alkanes named?
- Find the longest chain of carbons (called the parent chain), and use this number as the root name.
- Use the suffix “ane” to indicate only single bonds present.
- Number the chain starting at the end closest to the branching.
- Give the location of the alkyl group by the number of the parent chain carbon that it is attached to.
- Put the alkyl groups in alphabetical order (i. e. ethyl before methyl)
- Use prefixes to indicate multiple branches (like di, tri)
- Substitution Syntax:
a. between numbers and words add a dash.
b. between numbers add commas
What is structural isomerism?
- Most hydrocarbons with four or more carbons exhibit structural isomerism
- Structural isomerism is when two molecules have the same molecular formula but different arrangements of atoms in space
- Different structural arrangements mean different chemical and physical properties
Explain the properties of Alkanes.
- The first four alkanes are gases. Alkanes with 5-40 carbons are liquids, 40 or more carbon atoms are waxy solids.
- Non polar molecules because of non-polar bonds combined with mostly symmetrical arrangement of h atoms
- London Dispersion forces are the only IMFS- alkanes generally have low melting and boiling points.
-As alkanes become larger, IMFS increase. More heat energy is needed to overcome these forces and thus melting and boiling points increase.
Explain Reactions of Alkanes.
- Alkanes are fairly unreactive (quite stable)
- They do not react with acids, bases, or strong oxidizing agents which makes them valuable as lubricating materials and as the backbone for structural materials such as plastics.
- They can undergo combustion and substitution reactions.
- Alkanes react in a specific type of substitution reaction called halogenation: a hydrogen atom is replaced by a halogen to form an alkyl halide.
How are alkyl halides named?
- Alkyl halides are named by writing the root of the halogen first, with the suffix -o, followed by the name of the parent alkane. If necessary, use numbers to denote the location and write substituent groups alphabetically.
What is the polarity of alkyl halides?
- Due to the high electronegativity of halogens, alkyl halides are often polar molecules with dipole-dipole IMFS.
- Boiling and melting points of alkyl halides are higher than those of corresponding alkanes.
Give a general explanation of Alkenes.
- Alkenes contain one or more double bonds.
- General formula: CnH2n
- Unsaturated hydrocarbons
- Many of the flavours, hormones, and insect pheromones belong to the alkene family.
Give a general explanation of Alkynes.
- Alkynes contain one or more triple bonds.
- General formula: CnH2n-2
- Unsaturated hydrocarbons
- Alkynes have been used as fuels, poison, or to make plastics and other organic compounds
What are alphatic hydrocarbons?
Alphatic hydrocarbons have structures based on straight or branched chains or rings of carbon atoms.
How are alkenes and alkynes named?
- The main chain must indicate the double or triple bonds at the lowest position number (indicate position #)
- Alkenes end with -ene. Alkynes end with -yne.
- If more than one double bond exists use prefixes (diene, triene)
- When numbering the main chain, double and triple bonds take priority over alkyl groups.
What are stereoisomers?
- Stereoisomers have the same number of atoms, with the double bond in the same position, but with a different 3D geometry around that double bond.
- Cis- means that the two groups are on the same side of the double bond.
- Trans- indicates that they are on opposite sides.
- Stereoisomers cannot be changed from one to the other by simple rotation. Bonds would have to be broken and reformed. Stereoisomers are distinct compounds with different properties, such as different melting points.
