4.1-4.12, 4.19-4.21 Organic chem: PART 1

What are organic compounds?

Compounds that contain carbon atoms (except carbon dioxide, carbon monoxide and carbonate salts)

What are the simplest organic compounds?

Molecules that only contain carbon and hydrogen atoms bonded together

What are hydrocarbons?

Molecules that only contain carbon and hydrogen atoms bonded together

How are carbon and hydrogen atoms held together in hydrocarbons?

Through covalent bonding

What is covalent bonding?

The electrostatic force of attraction between the positive nuclei of two non-metal atoms and the negative shared pair of electrons

What is a displayed formula?

A 2D formula that shows how all the atoms in an organic molecule are bonded together

When would hydrocarbons be described as saturated?

If they contain ONLY carbon-carbon SINGLE bonds, so the molecule holds the max possible number of hydrogen atoms for a carbon chain

What are alkanes?

Non-cyclic hydrocarbons that contain only SINGLE c-c bonds

What are cycloalkanes?

Cyclic hydrocarbons that contain only SINGLE c-c bonds

What is the shape of the alkane display?

Straight, branched

What is the shape of the cycloalkane display?

Cyclic, ring

What is the alkanes general formula?

C_n H_2n+2

What is the cycloalkanes general formula?

C_n H_2n

What is the name of CH4?

Methane

What is C2H6?

Ethane

What is C3H8?

Propane

What is C4H10?

Butane

What is C5H12?

Pentane

What is C6H14?

Hexane

What equipment is required for a hydrogen combustion?

Funnel, wax (alkane), Anhydrous CuSO4, Vacuum pump, Limewater, cold water

Why is the combustion experiment set up in a cold water bath?

To cool and condense the water vapour

What type of reaction is a combustion reaction an example of?

An oxidation reaction - the C and H atoms from the hydrocarbon bond with O atoms

What is a structural formula?

A formula used to show how all the atoms in an organic molecule are bonded together

Explain why methane has a very low boiling point of -162 degrees C?

1. Methane has a simple molecular structure

2. There are forces of attraction between the molecules which are weak

3. Little energy needed to overcome them

Why are hexane and 3-methylpentane not easy to separate?

The boiling points are very similar

What can fractional distillation be used for?

Fractional distillation can be used to separate a mixture of hydrocarbons which have different boiling points

What equipment is required for fractional distillation?

Mixture (containing substances), fractionating column, Condenser

What is the first step of fractional distillation?

Mixture is separated into fractions through heating

What is the second step of fractional distillation?

Mixture is heated and substances vaporise

What is the third step of fractional distillation?

Vapours of substance rise and the lowest boiling point substance reaches the top of the gractionating column first

What is the fourth step of fractional distillation?

Vapours cool and condense into a liquid in the condenser

What is the fifth (and final) step of fractional distillation?

Separate liquids are collected

How does fractional distillation work?

Fill in the gap:

1. Separates mixture into _

2. Mixture is _ and substances _

3. Vapours of substance rise and the _ boiling point substance reaches the top of the fractionating column first

4. Vapours _ and _ into a liquid in the condenser

5. Separate liquids are collected

1. Separates mixture into fractions

2. Mixture is heated and substances vaporise

3. Vapours of substance rise and the lowest boiling point substance reaches the top of the gractionating column first

4. Vapours cool and condense into a liquid in the condenser

5. Separate liquids are collected

What is crude oil?

A mixture of many different hydrocarbons with molecules containing 1-80 Carbon atoms - it has a thick gloopy texture

What is fuel?

A substance that you burn to release heat energy

What are the main problems associated with burning hydrocarbon fuels?

Release of CO2, emission of greenhouse gases, carbon monoxide, nitrous oxides, sulfur dioxide

Petrol and diesel are unsustainable as crude oil is finite

Compare the temperature at the bottom of the column to the temperature at the top of the column

Temperature at bottom around 400-500 degrees C, while temperature at top about 0-25 degrees C

What leaves through A?

Bitumen, a thick, liquid-like mixture that does not boil in the column

What is bitumen used for and how many carbons does it have?

Surfacing roads and rooves, has > 30 Carbons

What leaves through B?

Fuel oil

What is fuel oil used for and how many carbons does it have?

Fuel for large ships and power stations, 20-30 carbons

What leaves through C?

Diesel oil

What is diesel used for and how many carbons does it have?

Fuel for lorries and trains, 15-20 carbons

What leaves through D?

Kerosene

What is kerosene used for and how many carbons does it have?

Fuel for aircraft, 11-15 carbons

What leaves through E?

Petrol/gasoline

What is petrol used for and how many carbons does it have?

Fuel for cars, 5-10 carbons

What leaves through F?

Refinery gases

What are refinery gases and how many carbons do they have?

Natural gases for domestic heating and cooking, e.g. methane, ethane. 1-4 carbons

What is meant by ‘volatile’ in chemistry?

Volatile means how easy it is for a substance to evaporate. Lighter substances are more volatile

What is meant by ‘viscosity’ in chemistry?

Viscosity is a liquid’s resistance to flow. More viscous fluids flow less easily

What is the trend in colour as the fractions get heavier?

Darker in colour in bitumen and fuel oil from the higher boiling points