Paper 2 C7- Organic Chemistry Flashcards
Define crude oil
Remains of plankton and other living material buried in mud
Explain how crude oil is formed
- Dead plankton and plants sink to the seabed
- They are buried between layers of sand and mud (sedimentary) and don’t rot
- Immense heat and pressure breaks them down into crude oil
Give two properties of crude oil
- Finite
- Mixture of mostly hydrocarbons
Define hydrocarbon
Molecule made up of only hydrogen and carbon atoms
Name the type of hydrocarbon that is more common in crude oil
Alkanes (saturated)
Give the general formula for alkanes
CₙH₂ₙ₊₂
Define homologus series
“Family” of compounds with similar properties due to having the same general formula
Name the alkane with 1 carbon atom
Methane
Name the alkane with 2 carbon atoms
Ethane
Name the alkane with 3 carbon atoms
Propane
Name the alkane with 4 carbon atoms
Butane
Give the molecular formula for methane
CH₄
Give the molecular formula for ethane
C₂H₆
Give the molecular formula for propane
C₃H₈
Give the molecular formula for butane
C₄H₁₀
Write the suffix for alkanes
-ane
Identify the type of bond that connects each atom in a hydrocarbon
Covalent
Give the term for a group of hydrocarbons with a similar number of carbon atoms
Fraction
Explain how the mixture of hydrocarbons in crude oil are separated
- Crude oil is heated and evaporated
- Hydrocarbons with higher boiling points condense quickly
- These leave the fractionating column at the bottom
- Hydrocarbons with lower boiling points condense later
- These leave the fractionating column nearer to the top
Identify two uses of the fractions produced from fractional distillation
- Fuel
- Feedstock (for the petrochemical industry)
Name the 6 types of fuel made from fractions in order of decreasing boiling points
- Bitumen
- Heavy fuel oil
- Diesel oil
- Kerosene
- Petrol
- Liquified petroleum gas
Identify the use of bitumen
Roads
Identify the two uses of fuel oil
- Ships
- Power stations
Identify the use of kerosene
- Aircraft fuel
Give four uses of fractions by the petrochemical industry
- Solvents
- Lubricants
- Polymers
- Detergents
Name the three properties that the size of a hydrocarbon affects
- Boiling point
- Viscosity
- Flammability
Describe the relationship between the size of a hydrocarbon and its boiling point
The longer a hydrocarbon, the higher its boiling point
The shorter a hydrocarbon, the lower its boiling point
Describe the relationship between the size of a hydrocarbon and its viscosity
The longer a hydrocarbon, the higher its viscosity
The shorter a hydrocarbon, the lower its viscosity
Describe the relationship between the size of a hydrocarbon and its flammability
The longer a hydrocarbon, the lower its flammability
The shorter a hydrocarbon, the higher its flammability
State why hydrocarbons make good fuels
They can combust to release energy
Write the word equation for the complete combustion of a hydrocarbon
hydrocarbon + oxygen —–> carbon dioxide + water
The hydrogen and carbon are ___________ in the complete combustion of a hydrocarbon
Oxidised
Identify the purpose of cracking
Breaks large hydrocarbons down into smaller ones to meet the demand for fuel
[Exam Q] Explain why large hydrocarbon molecules are cracked to produce smaller hydrocarbon molecules (2 marks)
- Greater demand for smaller molecules
—> They are more useful/better fuels/used to make polymers
Name the two types of cracking
- Catalytic cracking
- Steam cracking
Describe what catalytic cracking involves
Passing a hydrocarbon over:
- A zeolite catalyst
- At low pressure
- And high temperature
Describe what steam cracking involves
Reacting hydrocarbon with:
- Steam
- At high temperatures
Name the two products of cracking
- Alkanes
- Alkenes
In the equation for cracking, the number of hydrogen and carbon atoms are _________ on each side of the equation
Equal/the same
Give the general formula for alkenes
CₙH₂ₙ
Write the functional group for alkenes
C=C
State why alkenes are more reactive than alkanes
They have a C=C double bond
Give one synonym for alkenes
Unsaturated hydrocarbons
Name the first 4 alkenes
- Ethene
- Propene
- Butene
- Pentene
Write the suffix for alkenes
-ene