organic chemistry - topic 7 Flashcards
what is the formula for an alkane?
CnH2n+2
What does ‘saturated’ mean for alkanes?
it consists of only single bonds. c-c
Describe a homologous series.
Organic compounds that react in a similar way.
Name the first 4 alkanes.
1.Methane, 2.Ethane, 3.Propane, 4.Butane
Why does viscosity change for each hydrocarbon?
The shorter it is, the less viscous (gloopy) it is.
What length hydrocarbons are more volatile?
Shorter hydrocarbons are more volatile.
Why does the flammability change for each hydrocarbon
The shorter it is, the more flammable (easy to ignite) it is.
When will complete combustion happen?
when there is enough oxygen
Give the word equation for incomplete combustion.
hydrocarbon + oxygen → carbon dioxide + water (+ energy)
What happens to hydrocarbons during complete combustion?
they oxidise
why are they useful as fuels
Because of the amount of energy they produce during complete combustion.
How was crude oil formed?
Dead plants and animals (mainly plankton) became trapped in mud under a high temperature and pressure.
Give 2 problems with Crude Oil.
- It is a finite resource, non-renewable.
2. It’s a long chain
What is the first step of Fractional Distillation?
Crude oil is heated to around 450 degrees so it vaporises.