Chapter 14 alcohols Flashcards
(16 cards)
State the reaganet and conditions and write an equation or the oxidation of an alcohol into a carboxylic acid (3)
- acidiied K2Cr2O7 and relux
- OH(CH2)2OH +4(O) -> HOOC(CH2)2COOH +2H20
- (O) AND H20
Complete equation or complete combustion of C4H10O
C4H10O + 6O2 -> 4CO2 + 5H2O
Explain the differeance between alcohols having a higher boiling point than alkanes between heptane hexane and pentan -1 -ol (4)
- hptane has a longer chain so more poitns of contact
- heptane has stronger london forces
- pentan - 1-ol has hydrogen bonds that are stronger than london forced
- more energy is required to break hydrogen bonds
1-Bromobutane is an organic liquid with a boiling point o 102 degrees celcius. A sstudent prepare 1 - bromobutane by rewcting butan -1ol with sulfuric acid and sodium bromid
The student obtains and organic layer and an aquous layer with a lower density
Outline a method to obtain a pure sample o 1- bromobutane from the reaction mixture (3)
apparatus
* round bottom pear shaped lask
* heat source
* condenser
purification
* use a seperating funnel to seperate organic and aqueous layers
* drying with an anhydrou salt eg CaCl2
* redistillation
Alcohols can be onvereted into alkenes in an elimination reaction
the elimination of H2O from pentain - 2-ol form a mixture of organic products
Give the names and structures of all the organic products in the mixture
And how does the reaction leads to different isomer (6)
- elimination can produce a double bond in the 1 or 2 position through combination of hydroxyl group with hydrogen from either 1st of 3rd carbon
- this leads to the formation of structural isomers pent-1-ene and pent-2-ene
- pent-2-ene exhibits stereoiomerism / EZ isomerism / cis-trans isomerism it has two different groupss attatched to each carbon atom
- there are two possible isomers of pen-2-ene and three in total
Describe the oxidation reaction of butan-1-pl forming an aldehyde and a carboxylic acid.
explain using a diagram how the aldehyde can be produced in a labaraory contolling reaction conditions (6)
oxidation reaction forming aldehyde
* acid and dichromate/CrO7^2-
* heat and distillation
* organic product is butanal
* CH3CH2CH2CH2OH +(O) -> CH3CH2CH2CHO +H2O
oxidation reaction forming carboxylic acid
* acid and dichromate
* heat under reflux
* organic product is butanoic acid
* CH3CH2CH2CH2OH +2(O) -> CH3CH3CH3COOH + H2O
distillation
* diagram of appartus with condenser
* condenser has water flow
* collection of organic prouct
* product is eperate to prevent further oxidation to the carboxylic acid
Construct and equation for the complete combustion of an unsaturated alcohol with 5 carbon atoms (1)
C5H10O +7O2 -> 5CO2 + 5H2O
Explain the difference in solubility of hexan-1-ol and hexan-11,6-diol (1)
Hexane-1,6-diol has more Oh groups and forms more hydrogen bonds with water
At room temperature and pressure the firt four membrers of the alkanes are all gases but the first four alcohol are qall liquids explain difference in terms of intemolecular forces (2)
- alcohold have hydrogen bonds
- hydrogen bonds are stronger than london forces
Explain why 2-methylpropan-1-ol has a lower boiling point than butan-1ol (2)
- fewer points of contact in 2-methylpropan-1-ol
- so has fewer london forces which require less energy to break
What is the reaction for when an alcohol turns into an alkene (1)
elimination/dehydration
Butan-2-ol can be oxidised by heating with an oxidising agent write an equation for the reaction (2)
CH3CH(OH)CH2H3+(O) ->CH3COCH2CH3+H2O
Why is butan-2-ol classifies as a secondary alchol (1)
- the OH group is attatched to a carbon that is attatched to one hydrogen atom / two alkyl groups
What i the correct reagents for this converion
CH3CH2CHOHCH3 -> CH3CH2CHBrCH3 (1)
NaBr and H2SO4
What are the coditions for bromoethane being prepared when heating ethanol with NaBr(1)
acid catalyt
What is the volume of oxygen gas at room temperature and pressure requored for the combution of 1.25x10^-3 mol of propan-1-ol
135cmcubed
