O- Intro

Question 1

Displayed formula

Answer 1

chemical formula showing ALL BONDS in a molecule
- eg. C-O-H

Question 2

Structural formula

Answer 2

chemical formula showing arrangement of atoms in a molecule

Question 3

Skeletal formula

Answer 3

all C atoms represented as points & H atoms x shown

Question 4

General formula

Answer 4

shows mathematical relationship between atoms in an element

Question 5

Alkyne structure

Answer 5

R三R

Question 6

Haloalkane

Answer 6

R-X (halide)
- eg. -C-Cl

Question 7

Alcohol

Answer 7

R-OH

Question 8

Aldehyde

Answer 8

O
ll
/ \
R H

Question 9

Ketone

Answer 9

O
ll
/ \
R R’

Question 10

Carboxylic acid

Answer 10

R-C=O
`OH

Question 11

Amine

Answer 11

R-NH2

Question 12

Nitro

Answer 12

R-NO2

Question 13

Methyl

Answer 13

CH3

Question 14

Ethyl

Answer 14

CH3CH2

Question 15

Propyl

Answer 15

CH2CH2CH3

Question 16

Isomerism

Answer 16

When molecules have the same chemical formula
but diff. chemical structures

Question 17

Structural isomerism

Answer 17

Molecule w/ the same molecular formula
but diff. structural formula/ arrangement

Question 18

3 types of structural isomerism

Answer 18

1. chain
2. position
3. functional group

Question 19

Chain isomerism

Answer 19

• structural isomers (same molecular formula)
• same functional groups
• diff. arrangements of C skeleton

Question 20

Position isomers

Answer 20

• same C skeleton
• same functional groups
• functional groups at diff. C

Question 21

Functional groups that always go at the end of C chain

Answer 21

1. carboxylic acid
2. aldehyde
   (3. amine)

Question 22

What is an isomerism reaction?

Answer 22

• reactant and product have the same molecular formula
• diff. arrangement of atoms

Question 23

2 types of stereoisomerism

Answer 23

1. optical
2. geometric (E-Z)

Question 24

What are stereoisomers?

Answer 24

• molecules w/ same structural formula
• but atoms arranged differently in space

Question 25

How do we represent bonds in 3D?

Answer 25

- same plane- lines - going backwards- dashed bond - going forwards- wedged bond (triangular)

Question 26

What do we call molecules that are mirror images to each other, but are different molecules at the same time?

Answer 26

Non-superimposable

Question 27

What are optical isomers?

Answer 27

- enantiomers - have a chiral carbon-- 4 single bonds w/ 4 DIFF. GROUPS - labelling: +/- ; D/L ; R/S

Question 28

What is a 50/50 mixture of 2 enantiomers called?

Answer 28

Racemic mixture/ racemate

Question 29

How do we test for optical isomers?

Answer 29

- R & S rotate in opposite directions in plane polarised light -- if R rotates clockwise, S rotates anticlockwise

Question 30

Why do geometric isomers exist?

Answer 30

- ALKENES ONLY - restricted rotation around carbon-carbon double bond

Question 31

Naming E/ Z isomers

Answer 31

- Z= substituents of higher priority (higher Ar) on the zame zide - E= higher priority substituents diagonally opposite -- if immediate atom on substituent same (eg. CH3 vs CH2Br), decide using second atom down the chain (H vs Br) ∴ Br= higher priority

Question 32

Another way of saying E & Z isomers

Answer 32

Z- cis E- trans

Question 33

How would you show that a sample is the d isomer not the l isomer?

Answer 33

- pass plane polarised light thru a solution of each isomer - one isomer would rotate the plane at the polarised light clockwise, the other isomer would rotate it anticlockwise

Question 34

How would you show that a sample of lactic acid contained equal amounts of the d and l isomer?

Answer 34

- pass plane polarised light thru a solution of the isomers - if both isomers are present in equal amounts, plane of polarised light should not rotate

Question 35

Explain why cis and trans isomers of 1,2-dichloroethane do not exist.

Answer 35

C-C single bond can easily rotate

Question 36

State characteristics of an homologous series (alkanes).

Answer 36

1. same general formula 2. same functional group 3. chemically similar (react ~ way) 4. trend in physical properties (eg. bp↑ as Mr↑) 5. differ by CH2