Chapter 12 - Alkanes Flashcards
What are the properties of Alkanes?
- Non-Polar, hence don’t dissolve in Water
- Larger than alkane, greater the boiling point
- Short alkanes are gas at room temperature
- Increasing the Branching decreases boiling point as SA decreases and vDW forces are weakened
- Saturated Hydrocarbons
What is Petroleum?
Crude Oil, which contains different chains of alkanes
What is Fractional Distillation?
How does it happen?
Separating hydrocarbons in Crude Oil into seperate columns.
Done by evaporatingCrude Oil at the bottom of a fraction column with a furnace, smaller alkanes will evaporate and rise up and condense in a high column where its cooler
What is cracking?
What is Catalytic Cracking, what are the condition and what are products?
What is Thermal Cracking, what are the condition and what are products?
Cracking is the process of breaking long chains of Hydrocarbons into smaller, more usable ones.
Using a catalyst (Zeolite) to lower the conditions to 450 degrees and 1-2 atm pressure. It usually creates benzene rings/aromatic compounds and short hydrocarbons
Using 1000 degrees and 70 atm breaking long hydrocarbons into a high proportional of akenes and a low proportion of alkanes
What do you know about Alkanes in Combustion?
What do you know about Alkanes in Incomplete Combustion?
Hydrocarbons reacts with Oxygen to form Carbon Dioxide and Water, creating a large supply of energy but also a lot of pollution. Indicated by a blue flame
Hydrocarbons reacts with insufficient Oxygen which creates Carbon Monoxide, Water and Pure Carbon which is reacted to create an Orange flame. Also detected using a Carbon Monoxide detector
How do fossil fuels contribute to climate change?
Produces Carbon Dioxide when burnt which makes the Earth warmer as they are very good at absorbing energy
What is Smog?
How is it created?
Smog is caused by Hydrocarbons and Nitrous Oxide reacting together to make ground level ozone which restricts vision and aggravates the lungs.
Formed when Nitrogen reacts with Oxygen in the air then reacts with Hydrocarbons at high pressure/temperatures to create Smog
What is Acid Rain and how is it created?
What places form them?
What are the impacts of Acid Rain?
When Fossil Fuels burn and create Sulphur which reacts with Oxygen to make Sulphur Dioxide which dissolve in the moisture of the air to create Acid Rain
Chimneys, Power Stations and Industrial Waste
Destroying buildings, crops
What is a free radical?
An atom/molecule with an unpaired electron
What Mechanism creates 2 free radicals which are used to react with Hydrocarbons in the air, creating a catalyst whilst making Haloalkanes and side products?
Outline this Mechanism
Free Radical Substitution
(Initiation) Diatomic Cl breaks down in UV sharing electrons between Monoatomic Cl, this is Homolytic Fission.
(Step One Propagation) Cl radical gains Hydrogen from a Hydrocarbon creating a Alkyl free radical.
(Step two Propagation) Hydrocarbon free radical produced in step 1 reacts with a diatomic Cl to form a haloalkane and Cl radical
Process repeats making the Cl/Alkyl Free Radicals, side products
(Termination) Side products join together creating a new product
What are the 3 products that can be made in termination?
A large alkane (CH3 + CH3 > C2H6)
Haloalkane (CH3 + Cl > CH3Cl)
Diatomic Cl (Cl + Cl > Cl2)
What is a mechanism?
What is an intermediate?
Mechanism is a process breaking a reaction down in steps
An intermediate is a product used as a reactant into another product , creating a chain reaction
