Carbon compounds as fuels and feedstock Flashcards
What are organic compounds used for?
as fuels to run cars, to warm homes, and to generate electricity
What is crude oil?
a finite resource found in rocks. it was formed over million years ago from the remains of tiny, ancient sea animals and plants, mainly plankton, that were burried in the mud.
What is crude oil formed as?
a dark, smelly liquid, it is a MIXTURE of many different carbon compounds.
What is a mixture?
contains 2 or more elements or compounds that are not chemically combined together.
What does the compound, hydrocarbon, contain?
Hydrogen
Carbon
How can mixtures of liquid be separated?
By distillation as it separates
You heat the curde oil mixture so that it boils. the different fractions vaporise between different ranges of temperature. the vapour can be collected by cooling and condensing them.
What arw fractions?
Hydrocarbons with similar bioling points separated from crude oil
What are the first 4 alkanes?
Methane
Ethane
Propane
Butane
What are saturated hydrocarbons?
A hydrocarbon with only single bonds between its carbon atoms. This means that it contains as many hydrogen atoms as possible in each molecule.
It is also alkanes
General formula for alkanes
c2 h(2n+2)
What is the difference of long molecules and short molecules?
What is fractional distillation?
A way to separate liquids from a mixture of liquids by boiling off the substances at different temperatures, then condensing and collecting the liquids.
What happens when propane gas burns?
The carbon and hydrogen are oxidised completely when they burn like this.
Oxidation: adding oxygen in a chemical reaction.
What do all fossil fuels burn in the air?
Carbon dioxide and water
What is incomplete combustion?
When there is not enough oxygen. Instead of all the carbon in the fuel turning into carbon dixoide, carbon monoxide gas is also formed.
What is carbon monoxide?
It is a toxic gas, it is colourless and odourless. Your red blood cells pick up this gas and carry it aorund in your blood instead of oxygen.
Why do we crack hydrocarbons?
some of the heavier fractions from the fractional distillation of crude oil is not in high demand. Becuase they have large molecules with high boiling points, they are difficult to vaporise and do not burn easily. This is why we use cracking because we are able to break down the larger less useful hydrocarbons into smaller more useful ones.
Where does the process of cracking take place?
at a oil refinery in steel vessels called crackers. In the cracker, a heavy fraction distilled from crude oil is heated to vaporise the hydrocarbons.
VAPOUR IS EITHER PASSED OVER A HOT CATALYST OR MIXED WITH STEAM AND HEATED TO A VERY HIGH TEMPERATURE
What are the hdyrocarbons cracked as?
Thermal decomposition reactions. the large molecules split apart to form smaller, useful ones.
What is more reactive? Alkane or Alkene?
Alkene
