Alkanes Flashcards
Give the names and chemical formulas of the first four alkanes in the alkane homologous series
Methane CH₄
Ethane C₂H₆ or CH₃CH₃
Propane C₃H₈ or CH₃CH₂CH₃
Butane C₄H₁₀ or CH₃CH₂CH₂CH₃
Alkanes are considered _______ hydrocarbons.
Saturated
Alkanes are generally chemically _________
Unreactive
Alkanes are ______ in water, but ______ in organic solvents
Soluble, Insoluble
Give four physical properties as the number of carbon atoms increases down the alkane homologous series
- Melting and Boiling points increase
- Viscosity increases
- Flammability decreases
- Density increases
Why does the melting and boiling points of alkanes increase down the group?
Down the group,
- molecules becomes larger (more C atoms)
- leading to stronger intermolecular forces of attraction
- more energy required to overcome forces
- bp and mp increases
Why does the viscosity of alkanes increase down the group?
Down the group,
- Molecules become larger (more C atoms)
- leading to stronger intermolecular forces of attraction
- The molecules therefore tend to stick to one another more strongly
- Viscosity increases
What are the two reactions that alkanes can undergo?
- Combustion
2. Free Radical Substitution
What are the products of Combustion for an alkane
Carbon Dioxide and Water
What are the reagents and conditions required for Substitution Reactions to take place
UV light, Halogen gas (Chlorine, Bromine etc)
What are all the possible products of substitution reactions of Chlorine with Methane?
Chloromethane
Dichloromethane
Trichloromethane
Tetrachloromethane
What are two possible methods, reagents conditions of producing a desired alkane?
- Addition of Hydrogen to Alkene (Hydrogen Gas, Ni Catalyst, 200 Degrees Celsius)
- Cracking (Long chain alkane, 600 Degrees Celsius, Silicon (IV) Oxide or Aluminium Oxide)
What is the general formula for alkanes?
CₙH₂ₙ+₂
