7.2 Reactions of alkenes and alcohols (Triple) Flashcards
What is an alkene?
Unsaturated hydrocarbon. Contains a C=C bond.
General formula for alkenes is: CnH2n.
What is the test for alkenes? (Triple)
Add bromine water. Colour change occurs from orange to colourless.
Describe the combustion of
alkenes. (Triple)
They burn with smoky flames due to incomplete combustion
Describe the addition reactions of alkenes. (Triple)
Addition atoms across the carbon-carbon double bond so that the double bond
becomes a single carbon-carbon bond.
● With hydrogen - hydrogenation; requires a higher temperature and a nickel
catalyst
● With steam - hydration; requires high temperature, pressure, and
concentrated phosphoric acid (H3PO4) as a catalyst
● With Br2/Cl2/I2
- addition of halogens
What is an alcohol? (Triple)
An organic compound that contains an -OH functional group
State characteristics of
methanol, ethanol, propanol and butanol. (Triple)
● Dissolve in water to form a neutral solution.
● React with sodium to form hydrogen.
● Burn in oxygen.
● React with carboxylic acids in presence of acid catalyst to form esters.
What does the oxidation of alcohols lead to? (Triple)
Carboxylic acids
What are some uses of
alcohols?
● Fuels
● Solvents
● Drinks
State the conditions required for
fermentation of glucose and state the equation of the reaction. (Triple)
30 degrees Celsius, aqueous solution of the glucose, absence of air, yeast added;
C6H12O6→
2 CH3CH2OH + 2 CO2
What are carboxylic acids? (Triple)
Organic compounds that contain a COOH functional group
State characteristics of
carboxylic acids (Triple)
● Dissolve in water to form an acidic solution (contains H+ ions)
● React with metal carbonates to form carbon dioxide
● React with alcohols with an acid catalyst to produce esters
● React with metals to give off hydrogen gas
What type of acid is carboxylic acid? (Triple)
It is a weak acid.
Explain why carboxylic
acids are weak acids? (Triple, Higher)
They are partially dissociated in water, thus the pH of a carboxylic acid in a solution is not as low as a solution of a strong acid of the same
concentration.
What is an ester and how is it
formed? (Triple)
An organic compound containing a -COO- functional group, formed from
carboxylic acid and alcohol in the presence of a sulfuric acid catalyst.
What is characteristic
about this class of
compounds? (Triple)
They have a fruity smell.
