C6.2 Flashcards
(21 cards)
What is a homologous series?
Family of organic compounds with the same general formula, functional group and similar physical properties/chemical reactions, with each successive member differing by 1 CH2 group.
What makes the homologous series of alkanes?
- Same general formula
- Hydrocarbons (hydrogen and carbon atoms)
- All carbon atoms joined by single covalent bond (saturated)
What is the formula for alkanes?
C(n)H(2n+2)
What is an alkane?
Saturated hydrocarbons - maximum number of hydrogen atoms and no double bonds.
What is the name of the main type of reaction alkanes are involved?
Combustion reaction.
What is necessary for a complete combustion reaction and what occurs during the reaction?
- Plentiful supply of oxygen
- Carbon atoms oxidised to carbon dioxide
- Hydrogen atoms are oxidised to water
What is the balanced equation for a complete combustion reaction?
propane + oxygen > carbon dioxide + water
C3H8 + 5O2 > 3CO2 + 4H2O
What happens during an incomplete combustion reaction?
- Poor oxygen supply, water forms but carbon is oxidised to carbon monoxide - toxic gas, causes suffocation
- In some cases carbon isn’t oxidised at all
Give an example balanced equation for an incomplete combustion reaction?
ethane + oxygen > carbon monoxide + water
C2H6 + 2.5O2 > 2CO + 3H2O.
What is the difference between alkenes and alkanes?
Alkenes have carbon carbon double covalent bond.
- Alkenes are unsaturated wheres alkanes are saturated.
What is the general formula for alkenes and what are they?
C(n)H(2n)
Unsaturated hydrocarbons are there is a double bond, extra hydrogen atoms (or other atoms) can be added.
What are the first 6 prefixes (systematic names) and what is a mnemonic for the first 4?
meth - 1 eth - 2 prop - 3 but - 4 Monkeys Eat Plastic Bananas
What are addition reactions?
- Atom or group of atoms that combine to form larger molecules with no product.
E.g. ethene + bromine > dibromoethane
Describe a test for unsaturation of alkenes.
- Bromine water reacts with alkenes but not alkanes.
- It’s orange brown, when mixed with alkenes it turns colourless.
What is the functional group for alcohols?
-OH (hydroxyl group shown separately in the chemical formula)
What is the general formula for alcohol?
C(n)h(2n+1)OH
When alcohols undergo combustion reactions what are the products?
Combustion - carbon dioxide and water
Incomplete combustion - carbon monoxide and water
What other reactions can alcohols form?
- They can be oxidised to form carboxylic acids.
What determines how a molecule reacts?
Its functional group
What is the functional group for carboxylic acids?
-COOH (carboxyl group)
What is the general formula for carboxylic acids?
C(n)H(2n+1)COOH
