Organic Chemistry Flashcards
What bonds do alkanes have?
C-C single bonds
Alkane general formula
CnH2n+2
What is a homologous series?
A group of organic compounds that react in a similar way
Alkanes are saturated compounds. What does that mean?
Each carbon atom forms 4 single covalent bonds
What are the first 4 alkanes?
Methane, ethane, propane, butane
The shorter the chain length what happens to the viscosity?
Less viscous
The shorter the chain length what happens to the volatility?
More volatile, gas at a lower temperature, lower boiling point
The shorter the chain length what happens to the flammability?
More flammable
What are ‘bottled gasses’
Gasses stored under high pressure as liquids in bottles, happen to short-chain hydrocarbons
Hydrocarbon complete combustion equation
Hydrocarbon + oxygen –> carbon dioxde + water (+energy)
What is crude oil and how is it formed?
A fossil fuel, the remains of plants and animals that died millions of years ago and were buried in mud, high temperature and pressure, remains turn to crude oil, drilled from the rocks which is where its found
What is crude oil and how is it separated?
A mixture of different hydrocarbons and by fractional distillation
How does fractional distillation work?
.Oil is heated to a gas
.Gas enters a fractioning column
.Hot at the bottom and cool at the top (temperature gradient)
.Long chain lengths have high boiling points so condense quickly and drain out at the bottom
.The shorter chain lengths have lower boiling points so condense and drain out much later at the top where its cooler
.You end up with a crude oil mixture that has been separated into different fractions
What is LPG?
Liquid petroleum gas
What is cracking and why do we do it?
Splitting up long chain hydrocarbons, we do it to get smaller chain lengths as they are more useful
What type of reaction is cracking?
Thermal decomposition - breaking down molecules by heating them
Describe how to catalytic crack
.Heat long chain hydrocarbons to vaporize them
.Vapour is passed over a hot powdered aluminum oxide catalyst
.The long chains split apart on the surface of the catalyst - this is catalytic cracking
Describe how to steam crack
.Heat long chain hydrocarbons to vaporize them
.Mix them with steam
.Heat them to a very high temperature
.This is steam cracking
Word equation for cracking?
Long chain hydrocarbon –> shorter alkane + alkene
What type of bonds do alkenes have?
One C=C double bond
Are alkenes saturated or unsaturated?
Unsaturated
What are more reactive alkanes or alkenes? Why?
Alkenes, their C=C bond can open up to form a single bond and allow the carbon molecules to bond with other atoms
Name the first 4 alkenes
Ethene, propene, butene and pentene
Alkene general formula
CnH2n
State the standard equation for the incomplete combustion of alkene
alkene + oxygen –> carbon + carbon monoxide + carbon doxide + water (+ energy)
What will you see from the incomplete combustion of alkenes? What will you get energy wise?
Smoky yellow flame
Less energy than complete combustion
What is a functional group?
A group of atoms in a molecule that determines how that molecule typically reacts
What is the alkene functional group?
C=C
What type of reactions do alkenes usually undertake?
Addition reactions
What is hydrogenation?
The addition of hydrogen
Describe the process and product of hydrogenation
Hydrogen can react with the double bonded alkenes to open up the double bond and form the equivalent alkane, it is reacted in the presence of a catalyst
How do alkenes react with halogens?
In the same way as hydrogen, the C=C bond is broken and each atom in the covalently bonded halogen each takes one bond
Ethene + bromine –>
Dibromoethane
Why DI in them name Dibromoethane?
Two bromine atoms
Why ethane in the name dibromoethane?
Saturated
What color does bromine water turn if mixed with an alkene? Why?
Colorless, as the bromine will add across the double bond making a colorless dibromo-compound, decoloring it
What do you add to alkenes to form alcohols?
Steam
How can ethanol be made?
Mixing ethene with steam and passing it over a catalyst
When making ethanol from ethene industrially what happens after the reaction has taken place?
The reaction mixture is passed from the rector into the condenser, ethanol, and water both condense as they have a higher boiling point and unreacted ethene gas is recycled back into the reactor. The alcohol can then be purified from the mixture by fractional distillation
What is a polymer?
A long molecule formed when lots of monomers join together, this reaction is called polymerization
What conditions does polymerization need?
High pressure and a catalyst
What are plastics made of?
Polymers, usually from carbon-based alkene monomers
What is addition polymerization?
Lots of unsaturated molecules can open up their double bonds and join together to form polymer chains
What does the ‘n’ on a displayed formula of an addition polymer mean?
It shows there is a number of monomers
How do you get the polymer name from the monomer? Use Propene as an example
Put the word ‘poly’ in front of the monomer name and but the monomer name in brackets - poly(propene)
Alcohol general formula
CnH2n+1OH
Alcohol functional group
-OH
Name first 4 alcohols
Methanol, ethanol, propanol, butanol
What is the naming system?
The same as the alkanes but replace the final ‘e’ with an ‘ol’
Why is CH3OH correct but CH4O not?
It shows the -OH functional group
Describe the first 4 alcohols
.Flammable .Undergo complete combustion .Soluble in water with neutral pH .React with sodium to produce hydrogen .Oxidised to produce carboxylic acid
What is methanol and ethanol used as?
Solvents in industry, they can dissolve most things water can dissolve plus hydrocarbons, oils, and fats
What are the first 4 hydrocarbons used as? Example
Fuels, ethanol is used as a fuel in spirit burners - burns fairly clean and is non-smelly
Which alcohol is the one in wine and beer?
Ethanol, usually made via fermentation
Describe the process of fermentation
Fermentation uses an enzyme in yeast to convert sugars into ethanol, carbon dioxide is also produced, a reaction occurs in a solution so the ethanol produced is aqueous
Word equation for fermentation
Sugar –> yeast –> ethanol + carbon dioxide
Best conditions for fermentation
37’C
Slightly acid
Anaerobic conditions (no oxygen)
The functional group of carboxylic acids
-COOH
How do carboxylic acids get their name? and name the first 4
The names end in ‘anoic’ and start with the normal starters
methanoic acid, ethanoic acid, propanoic acid, butanoic acid
What does the functional group look like structurally?
A Carbon atom double bonded to an Oxygen atom and singly bonded to a hydroxide molecule
What does a carboxylic acid produce when it reacts with carbonates?
a salt, water and carbon dioxide
Ethanoic acid + sodium carbonate –>
sodium ethanoate + water + carbon dioxide
How do you name the salts produced in carboxylic acids reactions with carbonates?
the end in ‘anoate’
Why do carboxylic acids form weak acidic solutions? How does this compare them to strong acids of the same concentration?
When they dissolve in water and ionize by releasing the H+ ions they don’t ionize completely (not all the acid molecules releases their H+ ions), so they have a higher pH than other acids of the same concentration
Esters functional group
‘-COOH-‘
How are esters formed? (word equation)
alcohol + carboxylic acid –> acid catalyst –> ester + water
What acid catalyst is usually used?
Concentrated sulfuric acid
Ethanoic acid + ethanol –> acid catalyst –>
Ethyl ethanoate + water
What does condensation polymerization involve?
Monomers that contain different functional groups
What do the monomers do in condensation polymerization?
.React and form bonds, making polymer chains
.For each new bond that forms a small molecule, for example, water is lost which is why it’s called condensation polymerization
Ethane diol + hexanedioic acid –>
a polyester + water
A diol + a dicarboxylic acid –>
condensation polymer + water
What functional groups do amino acids have?
a basic amino group (NH2) and an acidic carboxyl group (COOH)
What is the smallest and simplest amino acid?
Glycine
What can amino acids form through condensation polymerization?
Polymers known as polypeptides
What do long chains of polypeptides make?
proteins
What gives proteins their different polymers and shapes?
The order of amino acids
What is DNA made of?
Two polymer chains of monomers known as ‘nucleotides’
What do sugars contain?
They are small molecules that contain carbon, hydrogen, and oxygen
What can sugars do?
React together through polymerization reactions to form larger polymers
