U4AOS1 - Categories, properties and reactions of organic compounds

Question 1

Relative strengths of the different forms of intermolecular bonding (strongest to weakest)

Answer 1

Hydrogen Bonding, Permanent Dipole-Dipole Bonding, Dispersion Force

Question 2

Effect of Length of C-C chain on relative intermolecular forces

Answer 2

increasing the length of the carbon chain results in strongest dispersion forces (higher chance of an interaction)

Question 3

Effect of Branching of C-C chain on relative intermolecular forces

Answer 3

branched molecules have a decreased surface area - increasing the area between molecules - thus, there is less opportunity for bonds to be formed between molecules, weaker dispersion forces

Question 4

Boiling Point (+ results of weaker and stronger intermolecular forces)

Answer 4

temperature required to turn a substance from a liquid to a gas (break the intermolecular bonds)

Weaker IF - lower boiling point
Stronger IF - higher boiling point

Question 5

Viscosity (+ results of weaker and stronger intermolecular forces)

Answer 5

the resistance of a substance to flow

Weaker IF - lower viscosity (less energy is required to break bonds)
Stronger IF - higher viscosity (more energy required to break bonds)

Question 6

Effect of Temperature on Viscosity

Answer 6

when substances are heated, viscosity will decrease, as more energy is available to overcome the intermolecular forces

Question 7

Flashpoint (+ results of weaker and stronger intermolecular forces)

Answer 7

lowest temperature at which an organic compound can ignite in the air

Weaker IF - lower flashpoint
Stronger IF - higher flashpoint

Question 8

Is flashpoint greater or less than boiling point?

Answer 8

Given flashpoint relates to liquid fuels - flashpoint must be lower than boiling temperature

Question 9

Addition Reactions (+ pathways)

Answer 9

The breaking of the C=C bond, to produce a hydrocarbon

• Addition of H2 - requires a metal catalyst (Pt, Pd or Ni)
• Addition of H2O (produces alcohols) - requires H3PO4 (or H+) @ 300 degrees
• Addition of other reactants - doesn’t require a catalyst

Question 10

Bromine Test

Answer 10

Type of addition reaction - checks for the presence of double bonds

if the solution is colourless - unsaturated hydrocarbons are present
if the solution remains red-brown - bromine didnt react

Question 11

Substitution Reactions (+ pathways)

Answer 11

Reactions where one or more of the hydrogen atoms are replaced by another atom or functional group

• Substitution of Halogen (requires UV light) - position it will replace can be determined by the story of the question
• Substitution of Haloalkanes (to produce alcohol) - requires a source of OH- (generally Na, or K)
• Polar group substitution (no catalysts)

Question 12

Oxidation of Alcohols

Answer 12

Requires an Oxidizing Agent: can be any acid (must include H+) - e.g. MnO4- or Cr2O7 2-

Primary Alcohols - converted to aldehydeds -> carboxylic acids

Secondary Alcohols -Ketones

Tertiary Alcohols - cannot be oxidized

Question 13

Esterification Reactions

Answer 13

Combinedd an alcohol and carboxylic acid

Requires Concentrated Sulfuric acid H2SO4 (l)

Question 14

Atom Economy

Answer 14

(include molar ratios)

Question 15

Yield of Reactions

Answer 15