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 of C=C double bonds.
• if two groups with the highest atomic number are on the same side of the double bond it is the Z isomer
• If they are on different sides it is the E isomer.
• four different groups around the double bond you use cahn inglod prelod

Question 17

what is a functional group and what are some examples of these?

Answer 17

-These are the atoms or groups of atoms responsible for most of a molecule’s chemical reactions.
- alcohol (-ol)
-aldehyde (-al) (c double bonded to o and single bonded to h)
-ketone (-one)m(c double bonded to o)
- carboxylic acid (-oic acid) ( c double bonded to o and single bonded to oh)
- ester (alkyl - oate) (o in carbon chain and c double bonded to another o)
- amine (-alkyl amine) (nh2 group)
- nitrile (-nitrile ) ( c triple bonded to n)

Question 18

what are the three different types of halogenoalkanes?

Answer 18

• primary secondary and tertiary
• the type of halogen determines how it reacts

Question 19

what is a primary halogenoalkane?

Answer 19

• Primary (1°) halogenoalkane - carbon joined to halogen is only attached to one other alkyl
  group

Question 20

what is a secondary halogenoalkane?

Answer 20

Secondary (2°) halogenoalkane - carbon joined to halogen is attached to two other alkyl
groups.

Question 21

what is a tertiary halogenoalkane?

Answer 21

Tertiary (3°) halogenoalkane - carbon joined to halogen is attached to three other alkyl groups.

Question 22

what are the three types of structural isomerism?

Answer 22

• chain ISMOERISM
• position isomers
• functional group Isomers

Question 23

what is the empirical formula?

Answer 23

• the smallest whole number ratio of the elements present in one molecule or formula unit of the compound

Question 24

how do you figure out the empirical formula of a molecule?

Answer 24

• Write out the mass or percentage of each element
• Divide each mass or percentage by the Ar of the element
• divide by the smallest number.
• If the values come out as near ½’s then times them by 2, if they are near 1/3’s then times by 3

Question 25

how do you figure out the molecular formula from the empirical formula?

Answer 25

• divide the relative formula mass of the molecular formula by the relative formula mass of the empirical formula (you will be given these values)

Question 26

what is the percentage yield?

Answer 26

• a measure of how efficient a reaction is
• percentage yield = actual yield /theoretical x 00

Question 27

how do you figure out the theoretical yield

Answer 27

• use the molar ratio between the limiting reagent and the desired product

Question 28

what is the atom economy?

Answer 28

• total mr of all products / total Mr of all reactants x 100