Structure And Physical Property relationships Organic Chem

Question 1

Molecules with London forces

Answer 1

Alkanes
Alkenes
Alkynes

Question 2

Molecules with dipole dipole forces between them

Answer 2

Slightly Polar molecules 
Aldehydes 
Ketones 
Alkyl Halides
Esters

Question 3

Molecules with hydrogen bonds

Answer 3

Alcohols

Carboxylic acids

Question 4

Effects of IMF and number and type if functional group

Answer 4

Melting and boiling points

Stronger IMF = higher boiling point/melting point= more energy needed for the molecules to separate and change phase

Question 5

Define vapour pressure

Answer 5

Pressure that an enclosed vapour exerts on the surface of a liquid

Question 6

Effect of IMF on vapour pressure

Answer 6

Weaker IMF - vapourise easily - higher vapour pressure

Question 7

Effects of IMF on odour

Answer 7

Non polar molecules with weaker IMF vapourise easily and therefore are more likely to have an odour

Question 8

Effect of IMF on flammability

Answer 8

Shorter chained Hydrocarbons - octane

Alkenes more reactive and therefore highly flammable

Question 9

Chain lengths effect on physical properties

Answer 9

Longer chain - higher boiling/melting point
Longer chains become more wrapped around each other = increases strength of IMF
More energy is then needed to separate it

Question 10

Chain lengths effect on physical properties

Answer 10

Longer chain - higher boiling/melting point
Longer chains become more wrapped around each other = increases strength of IMF
More energy is then needed to separate it

Question 11

Branches effect on physical properties

Answer 11

More branches - lower boiling point
As the molecules branch there are less places of attachment for other molecules
Molecules are not as closely drawn to each other

Question 12

Combustion reaction

Answer 12

alkane + 02 -> C02 + H20

Balance order: Carbons Hydrogens Oxygens

Question 13

What is esterifcation?

Answer 13

reaction between alcohols and carboylic acids

Esters have a characteristic smell

Question 14

esterification reaction?

Answer 14

Alcohol + carboxylic acid → Alkylalkanoate + H20

Question 15

Naming Esters?

Answer 15

Alkylalkanoate

First a branch which is the alcohol then the rest of the molecule which is the Carboxylic acid

the alcohol is labled as a branch and is the first part of the ester’s name

Question 16

Esterification conditions

Answer 16

H2S 04

sulphuric acid

Question 17

Substitution reaction?

Answer 17

Chemical reaction in which an atom or group of atoms in a molecule is replaced by another atom or group of atoms

Question 18

primary, secondary and tertiary carbons ?.

Answer 18

primary c→ bonded to one other carbon
secondary c→ carbon bonded to two other C-atoms
Tertiary c. → carbon bonded to 3 other C-atoms

Question 19

Alkyl halide reaction conditions? Describe reaction?

Answer 19

reaction condition ⇒ presence of heat and light

Alkanes react with halogens
Halo alkanes form and an HX Molecule also forms (where x is a halogen atom)

Question 20

Reaction with HX (x→Cl or Br) to produce haloalkanes . Reaction conditions? Reaction products? describe reaction ?

Answer 20

Tertiary alcohols → room temp
P+ s alcohols → high temps

Reaction between an alcohol and HX to form haloalkane

Reaction product → halo alkane + H20

Question 21

Reaction of bases and haloalkane to form alcohols. Reaction conditions? Describe reaction? Reaction products?

Answer 21

Conditions →Base first dissolved in ethanol

BaseSCeg K0H) and haloalkanes to produce alcohols

Products → alcohol and other elements that dont form alcohol (e.g. K-BR)

Question 22

Hydrogenation. Describe? Conditions? Products?

Answer 22

H2 added to an alkene → double bond breaks

Conditions → dissolved in nonpolar solvent → Pt Pd or Ni
.
product → alkane form of Molecule

Question 23

Halogenation. Describe? Conditions? products?

Answer 23

Halogen molecule added to alkene → double bond breaks and Halogen atoms are added

Conditions → room temp
product → alkane with 2 halogen atoms

Question 24

Hydnhalogenation . Describe? conditions? products?

Answer 24

Alkene + Hx → alkane with an X atom attached

Conditions→ no water present
product→ alkane with X atom attached

Question 25

Hydration. Describe? conditions? products?

Answer 25

Alkene + H20
Conditions→ H2S 04 or H3P04
product→ an alcohol

Question 26

Dehydnhalogenation. Describe? conditions? product?

Answer 26

elimination of HX from a haloalkane and the formation of a alkene (double bond)

Conditions → ethanol or NaOH or KOH and heat under reflux

products → alkene with an X atom + HX (where X is the some atom e. g. chlorine Cl)

Question 27

Dehydration. Describe? Conditions ? products?

Answer 27

Elimination of an H20 from an alcohol

Conditions → H2S04 H3P04
products → alkene + H20

Question 28

Thermal cracking → describe the process

Answer 28

High temperatures and pressures - no catalyst
Crack crude oil into smaller chained compounds
Products are mainly alkenes - used in plastic making
Thermal cracking gives rise to free radicals and unsaturated hydrocarbons
Free radical - molecular compound with an unpaired electron

Process –>
C10H22 are broken into two free radicals
Free radicals break onto a saturated Alkenes and smaller free radical
Two free radicals from step 2 combine to form saturated hydrocarbon

Question 29

Catalytic cracking. Describe the process

Answer 29

produces petrol with a higher octane rating

> heated crude oil passed into fracturing column and is passed over a catalyst
The column is hot at bottom and cool at top → substances with longer chains condense at bottom (higher Bp ) → substances with shorter chain lengths condense at top (lower BPs )

Uses zeolites as catalysts → complex with large latticeS of aluminum, silicon and oxygen

The heat and catalysts encourages the cracking of larger chained molecules