Flashcards in Chapter 9 Deck (16):
What is crude oil?
a naturally occurring product, that is made up of long chain molecules made up of hydrogen and carbon only
What is the long chain of molecules called?
What are the first 4 alkenes?
1 - methane
2 - ethane
3 - propane
4 - butane
What is the general formula for alkanes?
For the hydrocarbon ethane how many carbons and hydrogens does it have?
carbons = 2
hydrogens = 6
How can the long chain molecules be separated?
by fractional distillation
What is the method for separating the molecules using fractional distillation?
1 - crude oil mixture enters a small column and is heated to a high temp so most molecules are vaporised.
2 - the column is cooler at the top than the bottom, as the gaseous molecules rise up the column they condense until they reach their boiling points.
3 - they are then collected and removed.
What are the separate samples called?
In fractional distillation what is the temperature at the bottom and the top?
top = 25*c
bottom = 350*c
What are the names for all 7 fractions and what are they used for?
1 - refinery gas = bottled gas
2 - gasoline(fuel) = fuel for cars
3 - naphtha = making chemicals
4 - kerosene = aircraft fuel
5 - diesel oil = fuel for cars, lorries, busses
6 - fuel oil = fuel for ships, power stations
7 - residue = bitumen for roads and roofs
As you go up the column what do the hydrocarbons have?
- lower boiling points
- lower viscosity (flow easier)
- higher flammability (ignite easier)
What is it called when the chains re broken into 2 small chains?
What are the 2 ways of cracking hydrocarbons? How is it done?
1 - CATALYTIC CRACKING =
* the alkane is brought into contact with a powered aluminium oxide catalyst at moderate pressure and a temperature of around 500*c
2 - STEAM CRACKING =
* the hydrocarbon is mixed with steam and heated to a very high temperature (approximately 850*c)
What does the cracking process result in?
two products called = *alkane + *alkene
What is the general formula for alkenes?