Organic Chemistry

Organic Chemistry

C12 (Syllabus)

C10 (Coursebook)

Fuels

• coal, natural gas & petroleum produce carbon dioxide on combustion

• methane is the main constituent of natural gas

• petroleum is a mixture of hydrocarbons - use fractional distillation to separate into useful fractions

Uses of the fractions as:

• refinery gas for bottled gas for heating and cooking

• gasoline fraction for fuel (petrol) in cars

• naphtha fraction as a feedstock for making chemicals

• diesel oil for fuel in diesel engines

• bitumen for road surfaces

Multiple Choice

Petroleum is considered as a mixture because

• it can be burned as a fuel.

• it can be separated into fractions by distillation.

• it is a fossil fuel formed over millions of years.

• it is a thick, black liquid.

Multiple Choice

At which pipe: M or N are hydrocarbons with lower boiling points collected?

• M

• N

Multiple Choice

Fractional distillation separates crude oil based on the different __________ of the molecules in the mixture

• melting point

• boiling point

• freezing point

• chemical reactivity

Multiple Choice

Where do short chain hydrocarbons collect?

• At the top

• In the middle

• At the bottom

Multiple Choice

Shorter hydrocarbons have:

• Higher boiling points

• Lower boiling points

Homologous series

• hydrocarbon - contain hydrogen and carbon

• families of compounds with the same general formula and similar chemical properties

Multiple Choice

Compounds in the same homologous series have

• different general formulae and different chemical properties.

• different general formulae and similar chemical properties.

• same general formulae and different chemical properties.

• same general formulae and similar chemical properties.

Multiple Choice

Hydrocarbons are compounds that contain

• carbon only

• carbon and hydrogen only

• carbon, oxygen, and hydrogen.

• carbon, oxygen, hydrogen, and nitrogen.

Multiple Choice

Which formula represents a saturated hydrocarbon?

• A

• B

• C

• D

Alkanes

• saturated hydrocarbons

• contain only single covalent bonds

• generally unreactive, except burning

• complete combustion gives carbon dioxide and water

Alkenes

• unsaturated hydrocarbons

• contain one double covalent bond

• cracking is a reaction that produces alkenes

Saturated vs Unsaturated

hydrocarbons:

> molecular structures

• alkane - single bond only

• alkene - one double bond

> reaction with aqueous bromine:

• alkane - no change

• alkene - yellow/orange decolourised

https://www.youtube.com/watch?v=vBMGNzRYngk

Multiple Choice

The group that has single bonds only is called as

• alkenes

• alcohols

• alkanes

• ethers

Multiple Choice

Which statement about alkanes is correct?

• Alkanes are compounds containing carbon, hydrogen and oxygen.

• Alkanes are saturated hydrocarbons.

• Ethane is used to make poly(ethene).

• Methane is the only alkane that does not contain a double bond.

Multiple Choice

Which statement about alkanes is not correct?

• Alkanes are saturated hydrocarbons.

• Alkanes burn to release heat energy.

• Alkanes form carbon dioxide and hydrogen when they burn.

• Alkane molecules contain only single bonds.

Multiple Choice

What colour does bromine water turn in the presence of an alkene

• Orange

• Blue

• Colourless

• Green

Multiple Choice

Which one of the following is saturated?

• water

• C₄H₈

• C₄H₁₀

• C₅H₈

Multiple Choice

Classify the compound based on the functional group present.

• alkane

• alkene

• alkyne

• aromatic

Multiple Choice

Classify the compound based on the functional group present.

• alkane

• alkene

• alkyne

• aromatic

Multiple Choice

If an alkane has 20 carbon atoms, how many hydrogen atoms will it have?

• 20

• 22

• 40

• 42

Multiple Select

Hydrocarbon fuel + oxygen ----> ___+____

(Select 2)

• CO₂

• O₂

• H₂O

• C_xH_y

Multiple Choice

Write a Balanced Equation for this reaction:
C₂H₄ + 2 O₂ -->

• C₂O₂ + H₄

• CO₂ + HOH

• CO + H

• 2 CO₂ + 2H₂O

Multiple Choice

Which of the following reactions is/are an incomplete combustion reaction?

• C5H10 + 5 O2 → 5 CO + 5 H2O

• C2H4 + 3O2 → 2CO2 + 2H2O

• 2CH4 + 3O2 → 2CO + 4H2O

• Both A and C

Multiple Choice

Incomplete combustion is harmful to humans because it ___________________.

• increases the level of sugar in the blood

• produces large amounts of carbon dioxide

• decreases the amount of sugar in the blood

• produces carbon monoxide that reduces the level of oxygen in the blood

Cracking process

> the formation of smaller alkanes, alkenes and hydrogen from larger alkane molecules

> conditions required for cracking:

• high temperature (>500^oC)

• presence of catalyst

Multiple Choice

Which identifies the temperature used and describes the change to the alkane molecules during the cracking process?

• 100^oC; the alkane molecules become larger

• 100^oC; the alkane molecules become smaller

• 500^oC; the alkane molecules become larger

• 500^oC; the alkane molecules become smaller

Multiple Choice

Which reaction equation represents cracking?

• CH₄ + 2O₂ → CO₂ + 2H₂O

• C₂H₄ + Br₂ → C₂H₄Br₂

• nC₂H₄ → ( C₂H₂ ) n

• C₂H₆ → C₂H₄ + H₂

Polymerisation

chemical process of monomers joining together to form polymers, often it takes many thousands of monomers to make a single polymer

Multiple Choice

What is a polymer?

• a very light material that is highly flammable

• a fossil fuel

• a large molecule made from many monomers joined together

• a molecule made up of only polar bonds

Multiple Choice

What is Polyethene made from?

• Ethene

• Ethane

• Propane

• Propene

Multiple Choice

Large molecules made up of small monomers are called

• polymers

• monomer

• allotrope

• functional group