Organic Chemistry Flashcards
What is crude oil?
A fossil fuel consisting of ancient biomass.
It is a finite resource
What is a hydrocarbon?
A compound made up of only hydrogen and carbon.
What are alkanes?
Saturated hydrocarbons.
Formula of alkanes?
CnH2n+2
What is a homologous series?
Similar chemical properties.
Describe the combustion of hydrocarbons?
Exothermic reaction occurs when hydrocarbons react with oxygen.
Complete combustion produces carbon dioxide and water.
Incomplete combustion produces carbon or carbon monoxide and water.
Describe the physical properties of alkanes?
The first few in the series are gases then liquids then solids.
Boiling points and viscosity increase as molecules get bigger.
Volatility and flammability decrease as molecules get bigger.
Poor reactivity.
Viscous meaning?
Thick consistency.
Volatile meaning?
Easily evaporated.
Process of fractional distillation?
Crude oil is heated and vaporised.
Vapor rises up from the bottom of the fractionating column.
The bottom is hotter at the bottom and cooler at the top.
Hydrocarbons cool as they go up the column.
They condense at different heights since they have different boiling points.
What happens to large molecules in fractional distillation?
They have a high boiling point so they are collected at the bottom.
What happens to small molecules in fractional distillation?
Low boiling points so they are collected at the top.
What is cracking?
Large hydrocarbons are thermally broken down into smaller and more useful molecules.
What type of reaction is cracking?
Thermal Decomposition.
Steam cracking?
Heated to vapor
Mixed with steam
Heated to high temperatures
