Organic Chemistry Flashcards
(15 cards)
What is a hydrocarbon?
Molecules made up of hydrogen and carbon atoms only.
What is crude oil?
A mixture of a very large number of compounds, but mostly hydrocarbons.
What are the uses of crude oil?
Fuels, electricity and making plastics, solvents and hundreds of other goods.
What is the general formula of an alkane?
CₙH₂ₙ₊₂.
What are the first five alkanes in order of size?
Methane, ethane, propane, butane and pentane.
How do properties of alkane change with length?
The boiling and melting points increase due to stronger intermolecular forces, viscosity (fluid’s resistance to flow) increases and flammability decreases.
What is the process of fractional distillation?
- Crude oil is heated and vaporised.
- In the column, there is a temperature gradient, and the vapourised hydrocarbons condense into fractions depending on their boiling point.
What is complete combustion of alkanes?
Burning in a plentiful oxygen supply, producing carbon dioxide and water vapour as only products, with lots of heat energy.
What is incomplete combustion of alkanes?
It occurs when there’s insufficient oxygen, leading to the formation of carbon monoxide, carbon soot and water.
Why is cracking necessary?
It converts large, less useful hydrocarbon molecules into smaller, more valuable and useful ones, like gasoline and alkenes.
What conditions are required for cracking?
High temperature and a (hot) catalyst or high temperature and steam.
What are the products of cracking?
Alkanes and alkenes.
What is an unsaturated hydrocarbon?
A hydrocarbon with one double bond (alkenes).
What is the general formula for alkenes?
CₙH₂ₙ.
What is the test for unsaturated hydrocarbons (alkenes)?
Bromine water will turn from brown to colourless.
