Reactions and mechanisms Flashcards
(24 cards)
How do you test for a C=C bond? what are the observations? Draw it out with ethene
place 1cm3 of Br water into a test tube and add 10 drops of alkene
observations: brown water turns colourless
how many ways are alkenes made? name them all and their conditions
2 ways
1. Dehydrogenation of halogenoalkanes (NaOH in ethanol, elimination rxn)
2. Dehydrogenation of alcohols (H2SO4, conc, heated under reflux, elimination rxn)
How many ways are alkanes made? Name them.
1
1. catalytic hydrogenation of alkenes (H2, 70atm, 60*C, Ni catalyst
How many ways are haloalkanes made? Name them.
2
1. Free radical substitution (Cl2(g), UV light)
2. Addition of Br to ethene (hydrogen halogen or Br2, electrophilic addition)
How many ways are alcohols made? Name them.
2
1. Acid catalysed hydration of ethene (H3PO4, 300*C, 60 atm, additio reaction)
2. Halogenoalkane + OH- (NaOH (aq) heat under reflux, nucleophilic substitution)
Describe the process of a dehydrogenation of halogenoalkanes, what does this make? Draw it out using 1-bromoethane.
makes alkenes
NaOH in ethanol, reflux at 78*C
elimination reaction
describe the process of catalytic hydrogenation of alkenes. what is made? draw it out using prop-1-ene
alkane made
H2, 70atm, 60*C, Ni catalyst
addition reaction
Describe the process of acid catalysed hydration of ethene. What is made? draw it out using ethene
makes an alcohol
H3PO4, 300*C, 60atm
addition reaction
Describe the process of addition polymerisation of ethene. draw it out.
high temp and press, zeolite catalyst
polymerisation
Describe the process of addition of Br to ethene. draw it out using ethene.
bromine water
electrophilic addition
Describe the process of the addition of hydrogen halides to symmetrical alkenes. Draw it out using ethene.
hydrogen halide + alkene
electrophilic addition
Describe the process of the addition of hydrogen halides to unsymmetrical alkenes. Draw it out using propene.
propene + HX
electrophilic addition
Describe the addition of OH to a halogenoalkane. Draw it out using chloromethane.
NaOH (aq) and heat under reflux
Describe the industrial prep of ethanol from ethene. Draw it out.
H2O (steam), H3PO4, 300*C, 60atm
Addition reaction
Describe the process of fermentation.
glucose, yeast catalyst, room temp and press
fermentation
describe the process of the dehydrogenation of primary alcohols.
H2SO4 (conc), heated under reflux
elimination reaction
describe the process of the oxidation of a primary alcohol. Draw it out using propan-1-ol
acidified potassium dichromate (H+/Cr2O72-)
Oxidation
Describe the process of the oxidation of a secondary alcohol. Draw it out using propan-2-ol.
acidified potassium dichromate (H+/Cr2O72-)
Oxidation
Describe the process of the esterification of carboxylic acids.
conc H2SO4 (catalyst), heat under reflux
Esterification reaction
what is the test for a carboxylic acid? give an example.
the production of CO2
2CH3COOH + Na2CO3 -> 2CH3COO-Na + H2O + CO2
how do you know when a reaction is an addition reaction?
two molecules combine to form a single product.
How do you know when a reaction is nucleophilic substitution?
Happens when a nucleophile (electron-rich species) replaces a leaving group in a molecule. Common in halogenoalkanes.
How do you know when a reaction is electrophilic addition?
Similar to addition reactions but involves electrophiles (electron-poor species) attacking a molecule with a π-bond.
How do you know when a reaction is an elimination reaction?
The opposite of addition, where atoms or groups are removed, forming a π-bond. Common with alcohols and halogenoalkanes
