organic chem Flashcards
What is crude oil and how is it formed?
Crude oil is a fossil fuel formed under the sea from the remains of tiny plants, animals, and bacteria over millions of years under high pressure and moderate temperatures, without oxygen.
Example sentence: Crude oil is extracted from underground reservoirs and refined to produce various petroleum products.
What is a hydrocarbon?
A hydrocarbon is a compound made of only hydrogen and carbon atoms.
Example sentence: Methane, the main component of natural gas, is a simple hydrocarbon.
How are the different components of crude oil separated?
Through fractional distillation, which separates hydrocarbons based on their boiling points.
Example sentence: The process of fractional distillation involves heating crude oil in a fractionating column.
What happens to hydrocarbons with higher boiling points during fractional distillation, and why?
They condense and are drawn off at the bottom of the fractionating column because they have longer chains and stronger intermolecular forces.
Example sentence: Heavy hydrocarbons like bitumen are collected at the bottom of the fractionating column.
Name some uses of the different fractions obtained from crude oil.
Refinery gas: Bottled gas for heating and cooking
Gasoline: Fuel for cars
Kerosene: Aircraft fuel
Diesel: Fuel for lorries and buses
Bitumen: Making roads
Example sentence: Gasoline is a vital fuel for internal combustion engines in vehicles.
What is the main use of hydrocarbons?
As fuels, which release heat energy when burned.
Example sentence: Hydrocarbons like propane are commonly used in gas-powered appliances for cooking and heating.
What is the difference between complete and incomplete combustion of hydrocarbons?
Complete combustion produces carbon dioxide and water, while incomplete combustion also produces carbon monoxide and soot due to limited oxygen.
Example sentence: Incomplete combustion of hydrocarbons can lead to the formation of harmful pollutants.
Why is carbon monoxide dangerous?
It is a colourless, odourless gas that reduces the blood’s capacity to carry oxygen, making it highly poisonous.
Example sentence: Carbon monoxide poisoning can result from exposure to exhaust fumes in enclosed spaces.
What environmental problems are associated with burning fossil fuels?
Greenhouse effect (global warming) and acid rain, due to the emission of carbon dioxide, sulfur dioxide, and nitrogen oxides.
Example sentence: The combustion of fossil fuels contributes to the increase in greenhouse gases in the atmosphere.
What is an alkane and what is its general formula?
Alkanes are saturated hydrocarbons (contain only single bonds) with the general formula CnH2n+2.
Example sentence: Methane and ethane are simple alkanes commonly found in natural gas.
What is the general formula for alkenes and what distinguishes them from alkanes?
Alkenes have the general formula CnH2n and contain at least one carbon-carbon double bond, making them unsaturated and more reactive than alkanes.
Example sentence: Ethene is an example of an alkene used in the production of polyethylene.
What is a substitution reaction in the context of alkanes?
In the presence of UV light, a hydrogen atom in an alkane is replaced by a halogen atom.
Example sentence: Chlorination of methane is a common substitution reaction involving the replacement of hydrogen atoms with chlorine atoms.
How can you distinguish between saturated and unsaturated hydrocarbons using bromine water?
Unsaturated hydrocarbons (alkenes) will decolourise bromine water, while saturated hydrocarbons (alkanes) will not.
Example sentence: The addition of bromine water to an alkene results in the disappearance of the orange-brown color.
What is an isomer?
Isomers are compounds with the same molecular formula but different structural arrangements of atoms.
Example sentence: Butane and isobutane are isomers with different structures but the same molecular formula.
What is cracking and why is it important?
Cracking is the process of breaking long-chain hydrocarbons into shorter, more useful ones (alkanes and alkenes), making the refining of crude oil more profitable.
Example sentence: Cracking is a crucial step in the petrochemical industry to maximize the yield of valuable products from crude oil.
What is polymerisation and what problem is associated with the disposal of polymers?
-Polymerisation is the process of joining monomers to form polymers.
-Polymers are non-biodegradable, causing pollution when disposed of in landfills or burned.
Example sentence: The polymerisation of ethylene leads to the formation of polyethylene, a commonly used plastic material.
What are the two main methods of producing ethanol?
- Fermentation of sugars, which is a slower, batch process.
- Catalytic hydration of ethene, a faster, continuous process that produces pure ethanol.
Example sentence: Ethanol production through fermentation is widely used in the brewing and distilling industries.
a) Write the word equation for the reaction between an alkene and steam to make ethenol
b) State the 3 conditions for this reaction
a) ethane+water=ethenol
C2H4+H2O=C2H6O
b)
-60-70 atm of pressure
-300 degrees
-concentrated phosphoric acid catalyst
Draw a labelled diagram of the catalytic hydration of ethene
Check notivility organic chemistry
a) Write the word and chemical equation for fermentation
b) State the conditions for this reaction
a)
Glucose->carbin dioxide+ethenol
C6H12O6 → 2CO2 + 2C2H5OH
b)
-anareobic conditions
Draw a labelled diagram of how fermentation produces ethenol
chsck noitiblity
What is the formula fpr an alcohol
CnH2n+1
What os the difference between a repeat unit and a monomoer
repeat unit has no double bond, monomer does
List the 6 fractions of crude oil when fractional distillating
refinery gas - bottle gas for heating
gasoline - fuel in cars
kerosine - used in oil stoves
diesel - fuel in diesel ships
fuel oil - fuel for ships
bitumen - making roads
(as you go down:
-increase boiling point
-increasing viscocity
-darker colour)
Fuels obtained by fraction can cause impurities
Explain how the combustion of a common impurity in fuels can cause an environmental problem
-sulfur is the impurity
-when burnt produces sulfiur dioxide
-when evapourated, condenses and falls as acid rain
-this erodes soil
WHat is the catalyst used in cracking
sillica or allumina
