Nature's Chemistry Flashcards
State the definition of a homologous series
A homologous series is a family of compounds with the same general formula and similar chemical properties.
Describe and recognise a saturated and unsaturated compound
Saturated compounds only contain C-C single bonds.
Unsaturated compounds contain at least one C=C double bond.
State the test for saturation
If a compound is unsaturated it will decolourise bromine water.
State the definition for an isomer
Isomers are compounds with the same molecular formula but different structural formulas.
State the properties of an alkane, alkene and cycloalkane
Alkane - saturated hydrocarbons, insoluble in water and commonly used as fuels.
Alkene - unsaturated hydrocarbons, insoluble in water and commonly used to make polymers and alcohols via addition reactions.
Cycloalkane - saturated, cyclic hydrocarbon, insoluble in water, commonly used as fuels and solvents.
Describe an addition reaction
An addition reaction is when 2 (or more) molecules join together to form a larger one.
The reaction involves breaking a C=C double or triple bonds.
State and recognise the different types of addition reactions
Hydrogenation - reaction between an alkene and H2 forming an alkane.
Hydration - reaction between an alkene and water forming an alcohol.
Alkenes reacting with halogens forming dihaloalkanes.
State the uses of alcohols
Fuels - alcohols are very flammable and they burn with a clean flame.
Solvents - substances which may not be soluble in water may be in alcohols.
Describe the properties of alcohols
Smaller alcohols are soluble in water, after 4 carbons their solubility decreases (this is due to the size of the molecule increases).
As alcohols increase in size their melting and boiling point increases as the strength of the intermolecular force increases.
State the uses of carboxylic acids
Carboxylic acids are used in the preparation of preservatives, soaps and medicines.
Describe the properties of carboxylic acids
Small carboxylic acids (up to 4 carbons) are miscible (soluble) in water, any bogger are insoluble.
As the size of carboxylic acid increases the melting and boiling point increases, this is due to the increasing strength in intermolecular forces.
Name and recognise the functional group in carboxylic acids
Carboxyl (-COOH) functional group.
Exam tip
Check whether a question asks you to name or identify the functional group.
State the definitions of exothermic and endothermic reactions
Exothermic reaction - reaction which releases heat energy, means temperature rises
Endothermic reaction - reaction which takes in heat energy, means temperature decreases
