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.
