Ch10 Organic reactions Flashcards
general formula of alkenes
CnH2n
5 alkene reactions
combustion addition with halogens with hydrogen with steam
alkene reaction with hydrogen
forms an alkane
occurs in presence of a nickel catalyst
Combustion of alkenes
produces carbon dioxide + water
Why can’t alkenes be used as fuels
burn with a smokier, yellow flame than alkanes(incomplete combustion)
too reactive(have lots of empty space across the double bond)
release less energy per mole in combustion than alkanes
alkene addition reactions
molecules that react with molecule are added across their double bond
alkene reaction with halogen
reacts with orange bromine water to turn it colourless
is a test for unsaturated hydrocarbons
alkene reaction with water(steam)
forms an alcohol
ethene + steam ⇌ ethanol
Functional group of alchohols
-OH
General formula of alchohol
CnH2n+1OH
Uses of alchohols
fuels
solvents in perfumes, aftershaves and mouthwashes
Alcoholic drinks(ethanol)
Display formula of ethanol
H H l l H-C-C-O-H l l H H
Reactions of alcohol
combustion
oxidation
with sodium
with water
Complete combustion of alcohols
burns with blue clean flame
highly flammable
produces CO2 + H2O
Formation of ethanol
sugar solutions are fermented using yeast, producing aqueous solutions of ethanol
Reaction of alcohol with sodium metal
produces hydrogen and sodium alkoxide
e.g. sodium + ethanol –> sodium ethoxide + hydrogen
Oxidation of alcohols
Forms a carboxylic acid
Properties of alcohols
neutral pH short chain molecule low boiling point clean flame high flammability
Carboxylic acids
weak acid (partially ionises in water to form H+ ions) CH3COOH(aq) ⇌ CH3COO-(aq) + H+(aq)
ethanoic acid is vinegar
General formula of carboxylic acid
CnH2nO2
Functional group of carboxylic acids
COOH
Display formula of
- methanolic acid
- ethanoic acid
1.
O
//
H - C
\
O - H
2.
H O
l //
H - C - C
l \
H O - H
Functional group of esters
-COO-
Formation of esters
carboxylic acid + alcohol
uses an acid catalyst
-normally sulfuric acid
also produces water
How to create display formula of an ester
- lose hydrogen from carboxylic acid
- lose OH from alcohol and move H from left to right side
- replace H from carboxylic acid with the alcohol
Properties of esters
volatile(evaporate easily) distinctive smells(sweet and fruity)
carboxylic acid + carbonate
forms salt + carbon dioxide + water
