3 Organics 1 Flashcards by Shanon Garcia

What is crude oil?

A mixture of hydrocarbons

(which have different boiling points!)

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What is a hydrocarbon?

A molecule containing carbon and hydrogen only

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Why is crude oil considered to be a non-renewable energy source?

Crude oil takes many million of years to form in the Earth’s crust through heat and high pressures.

It does not renew itself at a sufficient rate for sustainable use

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Name the first four hydrocarbon in the alkane homologous series.

(Monkeys eat peeled bananas!)

methane

ethane

propane

butane

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What is an alkane?

A hydrocarbon with single C-C bonds only- no C=C double bonds

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What is the general formulae for alkanes?

C_nH_2n+2

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What is the general formulae for alkenes

C_nH_2n

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What is the name for C₈H₁₈ and what homologous series is it from?

octane

it is an alkane

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Alkanes only have a single bond between the carbon atoms.

What effect does this have on their reactivity?

What name is used for this sort of hydrocarbon?

Large number of hydrogen atoms blocking the C-C bond makes it difficult to get to and makes them less reactive.

They are said to be saturated with hydrogen

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What is the name for C₇H₁₄and what homologous series is it from?

heptene

It is an alkene

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Name the two alkanes with 9 and 10 carbons and give their molecular formulae

Nonane - C₉H₂₀

Decane - C₁₀H₂₂

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How do molecules in a particular homologous series relate?

- they have trends in physical properties

- they have similar chemical properties

they have the same functional group
they differ by CH2 groups

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What is the display formula for methane?

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Alkenes have a double bond between the carbon atoms.

What effect does this have on their reactivity?

What name is used for this sort of hydrocarbon?

There are fewer hydrogen atoms blocking the C=C bond. This makes it easy to get to and makes them more reactive.

They are said to be unsaturated

(They are not saturated with hydrogen!)

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Alkanes only have a single bond between the carbon atoms.

What effect does this have on their reactivity?

What name is used for this sort of hydrocarbon?

Large number of hydrogen atoms blocking the C-C bond makes it difficult to get to and makes them less reactive.

They are said to be saturated with hydrogen

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Name the two alkanes with 5 and 6 carbons and give their molecular formulae

Pentane C₅H₁₂

Hexane C₆H₁₄

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Name the two alkanes with 9 and 10 carbons and give their molecular formulae

Nonane - C₉H₂₀

Decane - C₁₀H₂₂

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Name the two alkanes with 7 and 8 carbons and give their molecular formulae

Heptane - C_{7}H_{16}

Octane - C_{8}H_{18}

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Name the two alkanes with 9 and 10 carbons and give their molecular formulae

Nonane - C₉H₂₀

Decane - C₁₀H₂₂

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What is the display formula for pentane?

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What happens to the intermolecular forces as you go down the alkane group?

How do you know?

There are more intermolecular forces down the alkane group

The boiling point increases down the group- more energy needed to overcome the intermolecular forces.

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What is the structural formulae for ethane?

CH₃CH₃

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What is the trend in volatility in the alkane group?

Hydrocarbons are more volatile the shorter their chain.

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What is the structural formulae for propane?

CH₃CH₂CH₃

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What property allows hydrocarbon fractions to be separated? Name the method used to separate them.

The hydrocarbon fractions have different boiling points They are separated using fractional distillation

What happens to the viscosity as the carbon chain increases in length?

Viscosity increases as chain length increases

Name the main fractions from crude oil ## Footnote *Hint: there are seven!*

Refinery gases Gasoline Naptha Kerosene Diesel Fuel Oil Bitumen

What happens to the bointing point as the carbon chain increases in length?

Boiling point increases as the carbon chain increases *methane is a gas, petrol is a liquid at room temperature*

What is an isomer?

Compounds with the same molecular formula but different structures

What happens to the colour as the carbon chain increases in length?

The hydrocarbon gets darker in colour as you increase the carbon chain

What is the addition reaction for propene and bromine water?

Why do you think alkenes are more 'useful' in the chemical industry?

They have C=C and so are more reactive They can be used to make polymers and other chemical products

What would you observe if methane is reacted with bromine in the presence of UV light?

Orange to colourless after about 20 minutes

What type of reaction is this?

**Substitution** The hydrogen was **substituted** with the bromine atom

What type of reaction is this?

**addition reaction** double bond is broken and two bromine atoms are **added** to either side of this

What is the test for alkenes?

add bromine water turns orange to colourless *alkanes need UV light for 20 minutes to turn colourless*

What is combustion?

The chemical reaction of a **fuel and oxygen** Complete combustion will produce **carbon dioxide and water** the reaction is **exothermic**

What are the main products for the **incomplete combustion** of methane?

carbon monoxide, carbon dioxide and water

What is the reaction for **complete combustion** of methane?

Why is carbon monoxide dangerous?

It is toxic ## Footnote - it binds irreversibly to your haemoglobin - it reduces the capacity of your blood to carry oxygen - person dies of asphyxiation

Most fuels contain sulfur. What is the environmental impact of this?

**sulfur reacts with oxyge**n to form **sulfur dioxide** non-metal oxides form acid when in water sulfuric acid forms- **acid rain** **-lakes become acidic- killing aquatic life** **-acid rain leaches minerals from soil- killing trees**

How can you tell that a fraction from a distillation tower still contains a mixture of hydrocarbons?

The fraction **boils over a range of temperature** rather than exactly at one temperature- it is not pure

Fuel are burnt in air which contains 78% nitrogen What is the environmental impact of this?

**nitrogen reacts with oxygen** to form **nitrous oxide** non-metal oxides form acid when in water nitric acid is formed- **acid rain** **-lakes become acidic- killing aquatic life** **-acid rain leaches minerals from soil- killing trees**

What product of combustion is most dangerous for the environment and why?

Carbon dioxide CO2 is a greenhouse gas which may lead to global warming

What are the products which can form from the thermal decomposition (cracking) of heptane?

*C₂H₄* & **C₅H₁₂** Must have 7 carbons one must be an alk*ene* and one **alkane**

Long (less useful) hydrocarbons are heated and passed over a **hot aluminium oxide catalyst.** This **breaks up** the long chain molecules **into a smaller alkane and alkene.** These smaller chain hydorcarbons are more useful What is this called?

Cracking

What are the conditions for cracking?

Hot aluminium oxide catalyst 600 - 700 °C

Explain why cracking is important to the chemical industry?

Forms **smaller more useful alkanes which are in higher demand** Forms **alkenes which can be used to make polymers** ***Cracking balances _supply and demand_ of these smaller chained alkanes and alkenes***

The products of cracking long chain hydrocarbons are shorter chained alkanes and alkenes. How could you test to show that an alkene is produced?

Collect gas by downward displacement Place a few drops of **bromine water** shake should turn **orange to colourless**

What is the name of the polymer formed form ethene?

poly (ethene)

What is the process that links together small double bonded molecules (monomers) to form a long chain molecules.

addition polymerisation

What is the name of the polymer formed form propene?

poly (propene)

What is the name of the polymer formed form chloroethene?

poly (chloroethene)

What is the name of the polymer formed form tetrafluoroethene?

poly (tetrafluoroethene)

Which type of polymerisation is shown below

addition polymerisation

Which type of polymerisation is shown below?

Condensation polymerisation

What are the differences between addition polymerisation and condensation polymerisation?

1. Addition polymers- **one type of monomer** Condensation polymers - **two different monomer** OR 2. Addition polymerisation forms a **pure polymer** Condensation polymerisation forms the polymer **and** a small molecule (e.g. H₂O)

Describe the environmental impact of plastics and what can be done

Plastic are **inert** (cannot be broken down by microorganisms) AND they give off **toxic gases** when burned (make them biodegradable, recycle them, reduce use, reuse them)

Name the monomer for this polymer

ethene

Name the monomer for this polymer

chloroethene

Name the monomer for this polymer

tetrafluoroethene

Name the monomer for this polymer

propene

Is this hydrocarbon saturated or unsaturated?

Unsaturated Contains a C=C double bond

What homologous series does this hydrocarbon belong to? What is its general formula?

alkenes C_nH_2n

What homologous series does this hydrocarbon belong to? What is its empirical formula?

alkanes C₅H₁₂ empirical formula is simplest ratio 5:12 is already the simplest ratio

Cracking is a thermal decomposition reaction. True or false?

true

Bromine water added to an alkene is an example of an addition reaction? True or false?

True double bond opens and two bromine atoms are added to either side of the double bond

Monomers used to make addition polymers are said to be saturated? True or false?

False Monomers are alkenes and contain double bonds They are unsaturated hydrocarbons

What is the main use of polyethene?

plastic bags and bottles

What is a main use of polypropene

crates and buckets

What are the main uses of polychloroethene?

window frames, plastic pipes

What is the main use of tetrafluoroethene

non-stick coating on pans

Name this organic compound

but-1- ene ## Footnote * longest C chain is 4 Cs* * double bond after 1st C*

Name this organic molecule

2 bromo 3 methyl but-2-ene ## Footnote * Br on 2nd C* * CH3 - methyl on 3rd C* * double bond after 2nd C*

Name this organic compound

2,4 dimethyl 3 ethyl hexane * longest chain 6 Cs long* * methyl group on 2nd and 4th C* * ethyl group on 3rd C*

What is a fuel?

A material which is burned to release energy (via heating and radiation (light))

In incomplete combustion, a poisonous gas and solid may be formed. Name these.

carbon monoxide and soot

When methane reacts with bromine it forms bromomethane. UV light is needed to remove a hydrogen and replace it with a bromine atom. What type of reaction is this?

substitution

When methane reacts with bromine it needs a particular condition. Describe this condition and the resulting product.

UV light for 20 minutes bromomethane

What do you call the hydrocarbon with a total of 8 carbon atoms in its chain with a double bond after its 3rd carbon?

oct-3-ene

What do you call the hydrocarbon with five carbon atoms in its chain and a double bond after its 1st carbon?

pent-1-ene