C7 - Organic Chemistry Flashcards
What are hydrocarbons
Structures made from carbon and oxygen
What is crude oil
A finite resource found in rocks and made from plankton that has been buried for millions of years
___ die and undergo high ___ and ____ to make fossil fuels
Plankton
Heat
Pressure
How many covalent bonds (single lines) should each carbon have in total?
4
What is the maximum number of bonds hydrogen can have?
1
Each line in displayed formula represents ——
A single covalent bond
Give the first 6 alkanes
Methane ethane propane butane pentane hexane
Crude oil is a mix of __and ___ chain hydrocarbons
Long and short
Crude enters the ___ column as a ____
Fractionating
Gas
Heat rises so gases ___ up the fractionating column.
When they reach their ____ points they ____
Rise
Boiling
Condense
__-chain hydrocarbons condense at the bottom of the cylinder as they have the ___ boiling points
Long
Highest
Longest chain hydrocarbons are siphoned off at around ___ degrees
340
Shorter chain hydrocarbons condense at around ____ degrees
40
Heavy fuel oil condenses at around __- degrees
260
Heavy fuel oil is very ___
Viscous
Diesel condenses at around __- degrees
180
Kerosene condenses at around ___ degrees
110
Petrol condenses at around __- degrees
40
Petrol is very ___
Runny
There is a temperature ___ in the fractionating column
Gradient
A temperature gradient means the fractionating column is ___ at the top and ___ at the bottom
Cooler
Hotter
The shortest chain hydrocarbons are released as ___ products called ____ gas through the ___ of the column
Waste
Refinery
Top
Give 3 properties of long chain hydrocarbons
Low flammability
High boiling point
High viscosity
Give 3 properties of short chain hydrocarbons
Low viscosity \
Low boiling point
High flammability
Short chains are more/less useful than long chains
More
What are alkanes
Hydrocarbons with only single bonds
Alkanes are ___ hydrocarbons
Saturated
What does a saturated molecule mean?
It only contains single covalent bond ( a saturated hydrocarbon has the maximum number of hydrogens possible
What is the general formula of an alkane
Cn H2n + 2
How many carbons does methane have? Ethane? Propane?butane?pentane?hexane?
1, 2, 3, 4, 5, 6,
What happens to the boiling points of methane -> hexane?
Increased
As longer chain hydrocarbons have more intermolecular forces of attraction which require more energy to overcome
What are Alkenes
Hydrocarbons with one double covalent bond (rest single covalent bonds)
General formula of an alkene
CnH2n
Name the first 5 Alkenes (there is no methene as there needs to be a double bond in an alkene)
Ethene
Propene
Butene
Pentene
Hexene
True or false: Alkenes are usually burnt as fuels
False
Why aren’t alkenes usually burnt as fuels?
They release less energy
Tend to burn with smoky flames (as more prone to incomplete combustion)
More useful for other things
True or false: alkenes are usually burnt as fuels
False
Due to the double bond alkenes are more __ rich
Electron
Which is more reactive - alkenes or alkanes?
Alkenes
Give one type of reaction alkenes can undergo
Addition reactions
What happens in an addition reaction?
C=C bond is broken and other atoms are added instead of
Give 3 things that destroy the C=C (create an addition reaction)
Halogens
Hydrogen
Water
Why does the bromine test work for alkenes?
The Alkene undergoes an addition reaction with bromine (as it is a halogen - in group 7)
What facilitates a reaction between hydrogen and an alkene
A nickel catalyst
What facilitates a reaction between alkenes and water
A phosphoric acid catalyst
What is the formula for phosphoric acid
H3PO4
Where should you write a catalyst in a reaction equation
Above the arrow - as it’s not used up during the reaction
When hydrocarbons undergo complete combustion what is produced?
CO2 and water (as normal)