C7: Organic Chemistry Flashcards
How is crude oil made?
Plankton buried underwater and compressed over a long time
What does crude oil consist of?
Hydrocarbons (Molecules made from only carbon & hydrogen) of different lengths
What are the 2 types of hydrocarbons?
Alkanes & Alkenes
What are alkanes made up of?
- Single-covalently bonded carbon atoms surrounded by hydrogen atoms (we say alkanes are saturated)
- Hydrogen makes 1 bond
- Carbon makes 4 bonds
What must hydrocarbons in crude oil be separated into before they can be used?
Fractions
How does fractional distillation work?
- Hydrocarbons evaporated and rise up the fractionating column where they recondense at different heights
- Longer alkanes have higher boiling points due to more energy needed to overcome the stronger intermolecular forces, so they recondense lower down the column
- Gases at top
- Liquid and thicker oil collect in the middle
- Top = really flammable
- Bottom = really viscous
What is the equation for complete combustion?
Fuel + oxygen -> carbon dioxide + water
What is the equation for incomplete combustion?
Fuel + oxygen -> carbon monoxide/carbon + water
What alkenes have higher viscosity?
Longer ones
What alkenes are more flammable?
Shorter ones
What can hydrocarbons be used to make?
Solvents, lubricants, detergents and polymers (used to make plastics)
What are polymers made from?
AlkEnes
What is an alkene?
A hydrocarbon with at least one double covalent bond
Alkenes are unsaturated
How do we test for alkenes?
Bromine water turns from orange to colourless
This is due to the bromine atoms bonding to the alkene by breaking the double bond. The molecule has been saturated
What is a problem with crude oil?
The demand for shorter alkanes is much higher compared to longer ones
What is cracking?
Breaking longer alkanes into a shorter alkane and an alkene
What does catalytic cracking require?
-Zeolite catalyst
-Temp of 550 degrees celsius
What does steam cracking require?
-No catalyst
-Higher temperature at >800 degrees celsius
What is an alcohol?
-An organic molecule with an -OH (hydroxyl) function group
-Always ends with -ol
What is the equation for complete combustion involving alcohol?
Alcohol + oxygen -> carbon dioxide + water
What is the equation for incomplete combustion involving alcohol?
Alcohol + oxygen -> carbon monoxide/carbon + water
What do ethanol + sodium make?
Sodium ethoxide + hydrogen
What does an alcohol produce when it is oxidised without combustion?
A carboxylic acid (-COOH)
What are polymers?
Long chained organic molecules of repeating sections made from monomers
What happens in addition polymerisation?
-Monomers joined together
-Must contain a double bond, which breaks in order to produce a single bond to bond to the next monomer
What is condensation polymerisation?
The polymerisation of different monomers that have two functional groups on the ends of the molecules
What does a carboxylic acid + alcohol produce?
An ester + water
What happens when an alcohol with -OH on both end reacts with a carboxylic acid with -COOH on both ends?
Makes a polyester while water is also produced
What do amino acids contain?
-An amino group (-NH2)
-A carboxyl group (-COOH)
What can amino acids be polymerised to make?
Polypeptides and proteins
What is DNA (deoxyribonucleic acid)
- A two-stranded polymer made from monomers called nucleotides
- Double helix structure
What is starch a polymer of?
Glucose
What is cellulose a polymer of?
Beta-glucose
What is a hydrocarbon?
A compound made up from hydrogen and carbon only
What does cracking long hydrocarbons using heat and a catalyst produce?
Short alkanes and alkenes
What is complete combustion?
- Lots of oxygen
- Roaring blue flame
What is incomplete combustion?
- Restricted oxygen
- Orange flame
What is hydrogenation/hardening?
- Alkenes + hydrogen -> Alkenes
- Done at 60 degrees C + nickel catalyst
What is hydration?
- Alkenes + water -> Alcohol
- Alkenes + hydrogen -> Halo alkene
What are uses of alcohol?
- Drinking
- Solvent
What happens when an alcohol reacts with sodium?
Fizzes
What happens when an alcohol reacts with oxygen?
Burns
What happens when an alcohol reacts with water?
Dissolves
What is the equation for fermentation?
- Sugar -> ethanol + carbon dioxide
- Yeast, 37 degrees C
What are uses of carboxylic acids?
- Vinegar
What happens when a carboxylic acid reacts with a carbonate?
It fizzes
What are the 4 bases and what do they bond with?
- A, C, T, G
- A always bonds with T
- C always bonds with G
What is a gene?
- A section of DNA
- Holds the information for making amino acids and proteins
What is the sugar phosphate backbone?
2 strands that go up the side around the DNA