9. Hydrocarbons Flashcards
What is a “hydrocarbon”?
A compound containing only C and H atoms
What is a Homologous Series?
Molecules with
- same general formula
- similar chemical properties
- gradation in physical properties
What are the names of the alkanes from 1C to 8C atoms in molecules?
What is meant by a saturated hydrocarbon?
A hydrocarbon where all C-C bonds present are single
What is the 3D shape of methane (CH4) ?
Tetrahedral
What is shown by a “Molecular Formula” ?
The types of atom and their relative abundance in a molecule. The abundance is shown as subscript
e.g
H2O
C3H8
NH3
CO2
What is shown in a “Full Structural Formula”?
All the atoms and all the covalent bonds connecting them in a molecule
What is shown in a shortened structural formula?
Each C in the chain is shown with everything bonded to it (not other C atoms in chain) No bonds need to be shown , although C=C bonds are allowed
What is the general formula of the alkanes?
What are the 2 main reactions of alkanes?
- Combustion
- Catalytic cracking
Why is catalytic cracking an important reactions for longer chain alkanes?
- To produce shorter chain, more useful alkanes
- To obtain alkenes which are useful reactants to make other products
What are the products of complete alkane combustion?
CO2 and H2O
How do we test for the products of combustion of a hydrocarbon?
What are possible harmful products of incomplete combustion of hydrocarbons?
What is meant by the term “isomers”?
Compounds with the same molecular formula but different structural formula.
Why does the boiling point of the alkanes increase as you add C (and H) atoms?
The larger molecules have stronger attractions between them that require more energy to be broken
What is meant by an unsaturated hydrocarbon?
A hydrocarbon with (at least) one C=C bonds present
What is a “hydrocarbon”?
A compound containing only C and H atoms
What is a Homologous Series?
Molecules with
- same general formula
- similar chemical properties
- gradation in physical properties
What is the general formula of the alkenes?
Cn H2n
What are isomers?
Compounds with the same molecular formula but different structural formulae
How are alkenes produced?
Catalytic cracking of longer chain alkanes
What is meant by a “functional group”?
The part of a molecule that is responsible for the chemical (and sometimes physical) properties of the compound.
What is the functional group of the alkene family?
C=C bond
What reactions do alkenes undergo?
Addition reactions
What specific name to we give to to the addition a halogen to an alkene?
Halogenation
What specific name to we give to to the addition of hydrogen to an alkene?
Hydrogenation
What is produced when an alkene undergoes a hydrogenation reaction?
An alkane
What is produced when an alkene undergoes a hydration reaction?
An alcohol
What is the chemical test for presence of unsaturation (C=C bond)
Rapidly decolourises bromine solution.
What specific name to we give to to the addition of water to an alkene?
Hydration
What is the general formula for the cycloalkanes?
Cn H2n
Are cycloalkanes saturated or unsaturated?
They are saturated molecules.
What are some uses of cycloalkanes?
- Fuels
- solvents
