Unit 2, Topic 6 - Homologous Series Flashcards
Which elements are present in alkanes?
Carbon and hydrogen
Name the first 8 alkanes and write the formula for them.
Methane, CH4
Ethane, C2H6
Propane C3H8
Butane C4H10
Pentane C5H12
Hexane C6H14
Heptane C7H16
Octane C8H18
What is the general formula for alkanes?
Cn H 2n +2
What type of bonding do alkanes have?
Covalent
Be able to give the name of the alkane, write the molecular formula, structural formula, and shortened structural formula.
Practice
As the length of the carbon chain increases what happens to the melting and boiling points of the alkanes?
As the C chain length increases the boiling point increases. As the size of the molecule increases, the intermolecular forces increase.
What does a substance react with during combustion?
Oxygen
When an alkane is fully burnt in oxygen what are the 2 products formed?
Carbon dioxide and water
Be able to write a balanced equation to show the reaction for the complete combustion of any alkane.
Practice
Name the substances that would form if there is incomplete combustion of any alkane.
Carbon monoxide/ or even carbon and water
Be able to draw a full structural formula for any branched chain alkane from the name.
Practice
What is meant by the term isomer?
Same molecular formula but a different structural formula.
Name three things that are different for isomers.
Structure, name, properties
Name the elements present in cycloalkanes.
Carbon, hydrogen
Name and give the formula for the first 8 members of the cycloalkanes.
Cyclopropane, C3H6
Cyclobutane C4H8
Cyclopentane C5H10
Cyclohexane C6H12
Cycloheptane C7H14
Cycloctane C8H16
Cyclononane C9H18
Cyclodecane C10H20
What is the general formula for cycloalkanes?
Cn H 2n
Be able to write the molecular formula and full structural formula for any named cycloalkane.
Practice
What are the products of the combustion of cycloalkanes?
Carbon dioxide and water
WHat type of carbon-to-carbon bond do alkenes have in their structure?
Carbon/carbon double bond
Be able to draw and identify isomers of alkenes and cycloalkanes.
Practice
Compounds with at least one carbon-to-carbon double bond are called…
unsaturated
What would you use to test a compound to see if it contained a carbon-to-carbon double bond?
Bromine water
What would you expect to observe if the compound did have a carbon-to-carbon double bond?
Goes from orange to colourless.
Write an equation to show the reaction between prop-1-ene and bromine
Practice
Write an equation to show how ethene will react with hydrogen to make ethane.
C2H4 + H2 —> C2H6
What is the name given to this type of reaction ? (ethene reacting with hydrogen to make ethane)
Hydrogenation
