Chapter 10&11

general formula of alkanes

CnH2n+2

what is this called?

cyclohexane

general formula of alkenes

CnH2n

what is a test to check if a molecule is unsaturated?

add Br2 (which is brown) because it will be added across the double bond of an alkene and turn colourless

how to calculate the degree of saturation

(max number of H possible - actual number of H) / 2

what is this called?

benzene

when a benzene ring is bonded to an alkyl group or a functional group, the ring structure is known as a _____ functional group

phenyl

how to identify an alcohol

OH

what is a primary alcohol?

OH attached carbon is bonded to 1 alkyl group

what is a secondary alcohol?

OH attached carbon is attached to 2 alkyl groups

What is a tertiary alcohol

OH attached carbon is attached to 3 alkyl groups

how to identify an amine

NH2

how to identify an aldehyde

CHO

how to identify a ketone

CO

how to identify a carboxylic acid

COOH

how to identify a primary amide

CONH2

how to identify an ester

COO

functional group priority scale (highest to lowest)

carboxylic acid, ester, aldehyde, ketone, alcohol, amine, alkyne and alkene, alkane

which homologous series have hydrogen bonding?

alcohols carboxylic acids, amines, amides

which homologous series have dipole-dipole attractions?

haloalkanes, aldehydes, ketones, esters

what is viscosity? And general info

viscosity is resistance to flow

• increases as chain length increases because forces of an attraction increase

• decreases as temperature increases because molecules gain enough energy to overcome the forces

what are dimers?

a molecule consisting of two identical molecules that are linked together

What are some properties of hydrocarbons?

• most are nonpolar with dispersion forces

• Insoluble in water but soluble in a nonpolar solvent

• Melting point and boiling point increases as chain length increases because dispersion forces get stronger

What are some properties of halo alkanes?

• contained bonds that are polar

• Have a weak dispersion forces but the carbon-halogen bond allows for dipole dipole attraction

Substitution reactions of halo alkanes

• reaction between an alkane and chlorine

• Reaction conditions: UV light

• Chlorine atom in molecule can be substituted by other functional groups

Addition reactions of alkenes

• carbon carbon double bond becomes a single bond

• Unsaturated compound become saturated

• atoms added across the double bond

A test for unsaturated molecules is to add bromine or iodine which are brown because they will be added across the double bond and become colourless.

Hydrogenation (addition of hydrogen) in alkenes

• solid nickel catalyst used

• Alkene and hydrogen gas forms an alkane

Halogenation (addition of group 17 elements)

• no catalysts used

• A di-substituted halo alkanes produced (2 halogens)

Addition of a hydrogen halide in alkenes

• alkene plus hydrogen halide produces haloalkane

• Note: can have isomers depending on position of the double bond

Hydration (addition of water) in alkenes

• catalyst is phosphoric acid (H2PO4)

• Temperature of 300°C

• Water is added across the double bonds of the alkene to form an alcohol

Combustion of alcohol

• produces carbon dioxide and water

• Highly exothermic

• Redox reactions

Oxidation of alcohols

• oxidised by KMnO4 or K2Cr2O7 in the presence of an acid (H+)

• Three types of alcohols: primary, secondary, tertiary

• Primary alcohols oxidise into aldehydes then carboxylic acid

• Secondary alcohols oxidise into ketones

• Tertiary alcohols are resistant to oxidation

Alcohol oxidation test

Acidified dichromate is orange and when Cr2O7 2- ions are reduced to Cr 3+ they turn green

Acidified permanganate ions are deep purple and when MnO4 -1 ions are reduced to Mn 2+ they become colourless

Ionisation of Carboxylic acid with water (and what is the reversible reaction)

• weak acid that ionise in water

CH₃COOH (aq) + H₂O (l) → CH₃COO- (aq) + H₃O+ (aq)

ethanoic acid (aq) + water (l) →

Reactions of Carboxylic acids with alcohols

• they are condensation reactions (water is eliminated) and specifically Esterification reactions

But not all Condensation reactions are esterification reactions

• H2SO4 (l) as catalyst

• Reverse reaction is hydrolysis

Hydrolysis of Esters

• hydrolysis is the breaking apart with the addition of water

Transesterification and the production of biodiesel

• triglyceride breaks down into three fatty acid methyl esters (biodiesel) and glycerol

• OH- catalyst

How to make an alcohol

• alkene + h2o and H3PO4 (l) catalyst and 300 degrees

• Alkene + HCl, then + OH-

How to make a carboxylic acid

• alkane + Cl2 and UV light → chloroalkane

• Chloroalkane + OH- → alcohol

• Alcohol + Cr2O7 2-/H+ → carboxylic acid

How to produce a polyalkene from an alkene

• catalyst and high pressures

Factors that can affect the yield of a reaction

• equilibrium reactions

• Losses when transferring between containers

• Decomposition of products

• Liquid lost due to evaporation

Formula for percentage yield

= actual yield / theoretical yield x 100

Formula for atom economy

= M(product) / M(all reactants) x100

OR

= m(product) / m(all products) x 100

Aims for the sustainable production of chemicals

• minimal waste

• replace fossil fuels with renewable resources

• products that are biodegradable or recyclable

• design processes are efficient and don’t harm the environment

Biopolymers

• made from feedstocks derived from plants

• Are biodegradable

• Most POLYMERS are made from fractional distillation of crude oil

• eg. biodegradable sutures

Advantages of biopolymers and bio solvents

• Manufacturing does not require use of finite resources (Cold, oil, natural gas)

• Can be obtained from plant sources which are renewable

• Many are biodegradable and many can be recycled

What do catalysts do and what are their advantages?

Allow reactions to take place at a much lower temperature

• reduces heating costs (saving energy resources)

• Increases reaction rate (more product in shorter time)

• Not consumed in the reaction so can be used continuously

alkane → haloalkane

• reagent: Cl₂ (g)

• conditions: UV light

haloalkane → alcohol

• reagent: OH^- (aq) or NaOH (aq)

• conditions: none

alcohol → carboxylic acid

• reagent: Cr₂O₇^2- (aq)

• conditions: acidic medium H⁺ (aq)

carboxylic acid → ester

• reactant: primary alcohol (l)

• conditions: H₂SO₄ (l)

alkene → chloroalkane

• reagent: HCl (g)

• conditions: none

alkene → alcohol

• reagent: H₂O (g)

• conditions: H₃PO₄ (s)

carboxylic acid → amide

• reagent: RNH₂ (l)

• conditions: none

alkenes → alkanes

• reagent: H₂ (g)

• conditions: Ni (s)

secondary alchohol → ketone

• reagent: H⁺ (aq) / Cr₂O₇^2- (aq)

• conditions: heat

Advantages of high atom economy:

• Produces less chemical waste → less environmental pollution.

• More efficient use of raw materials → lower costs.

• Less money spent on waste treatment and disposal.