introduction to organic chemistry (MDY)

Question 1

What is the general formula?

Answer 1

An algebraic formula that can be applied to chemicals in its ‘family’ e.g. alkanes alkenes alcohols etc.
cn h2n+2 - alkanes

Question 2

What is the molecular formula?

Answer 2

the acC2 total number of atoms in a molecule or element e.g. Ethane = C2 h6

Question 3

What is the empirical formula?

Answer 3

The simplest whole number ratio of atoms in a compound. e.g. Ethane = CH3

Question 4

What is the structural formula?

Answer 4

The arrangement of atoms in a molecule without showing all the bonds. no lines that display the bonds.

Question 5

What is the skeletal formula?

Answer 5

shows the bonds of the carbon skeleton only. hydrogen and carbon atoms are not shown but functional groups are. each point is a carbon.

Question 6

What is the displayed formula?

Answer 6

shows the arrangement of atoms showing all the bonds and atoms in the molecule.

Question 7

what is a homologous series?

Answer 7

• ## a group of compounds that have the same functional group and general formula

Question 8

What are the nine homologous series? and their prefix/suffix?

Answer 8

Alkanes - ane
alkanes (branched) alkyl-
alkenes - ene
alcohols - ol
aldehydes -al
ketones - one
carboxylic acids - oic acid
halogenoalkanes fluoro-/chloro-/bromo-/iodo-
cycloalkanes cyclo- -ane

Question 9

What is nomenclature?

Answer 9

the naming of molecules according to IUPAC.

Question 10

How do we use nomenclature to name molecules?

Answer 10

1. find the length of the stem by finding the longest continuous chain of carbons.
2. the functional group will tell yu the suffix of the name e.g. if the functional group was OH then the molecule would end in -ol
3. number the carbon so that the functional group sits on the lowest possible numbered carbon.
4. make a note of the carbon number the functional group is attached to. and place this number before the suffix.
5. any side chains and less important functional groups are written as prefixes in alphabetical order.
6. if there is more than one identical functional group or side chain put di- [2] or tri[3]4 or tetra[4] etc.

Question 11

what is a structural isomer?

Answer 11

structural isomers have the same molecular formula but a different structural formula.

Question 12

What is a chain isomer?

Answer 12

a molecule with the same molecular formula but a different arrangement of the carbon skeleton.

Question 13

What is a positional isomer?

Answer 13

a molecule with the same molecular formula but different position of the functional group on the carbon skeleton

Question 14

What is a functional group isomer?

Answer 14

a molecule with the same molecular formula but different functional group

Question 15

What is a stereoisomer? (E/Z)

Answer 15

stereoisomers have the same structural formula but a different arrangement of atoms in space

Question 16

What is E-z isomerism and how are the E and Z isomers decided?

Answer 16

• E- Z isomerism is caused by the limited rotation about C=C double bonds.
• if two groups with the highest atomic number are on the same side of the double bond it is Z isomer
• If they are on different sides it is the E isomer.