Chemistry Unit 2 | Fuels, Hydrocarbons and Homologous Series (copy)

What is a fossil fuel?

A fossil fuel is a fuel formed from the remains of living organisms.

What is a fraction?

A fraction is a group of compounds with similar boiling points .

What are hydrocarbons?

A hydrocarbon is a compound which only contains the elements carbon and hydrogen.

What does the complete combustion of a hydrocarbon produce?

Carbon dioxide and water.

What happens if the oxygen supply in combustion is not good?

Incomplete combustion takes place, where carbon monoxide is created, and carbon.

One of the signs of this is a yellow, sooty flame.

What is any reaction or process called which gives out energy?

Exothermic.

What is any reaction or process called which takes in energy?

Endothermic.

What is the specific heat capacity of water?

4.18kJkg(-10)C(-1)

What is the formula to find out the energy gained by water that the fuel has produced?

Eh = c m △T

What does Eh represent?

The energy gained by the water.

What does the c represent?

Specific heat capacity of water ( 4.18kJkg(-10)C(-1)).

What does m represent?

The mass of water heated ( 1ml of water = 1g of water ) the mass of water must be in kg to match the units of c.

What does △T represent?

The change in temperature of the water.

What are 2 main problems with experiments to find the energy released by fuel?

• Lots of heat energy is lost to the surrounding air and apparatus.

• The alcohol is burning with a yellow, sooty flame which is a sign of ‘incomplete combustion’. This means the alcohol is not burning efficiently, and is not giving out the maximum heat energy possible.

What is the shortened structural formula and ( molecular ) formula for ethane?

Shortened structural formula = CH(3)CH(3)

( Molecular ) Formula = C(2)H(6)

What is the table shown to represent the prefixes?

Prefix

1. Meth-

2. Eth-

3. Prop-

4. But-

5. Pent-

6. Hex-

7. Hept-

8. Oct-

9. Non-

10. Dec-

What is the general formula for alkanes?

CnH2n + 2

All alkanes end in -ane

What are some uses of Alkanes?

Methane = Used for cooking, heating, Bunsen burners and in power stations to produce electricity.

Propane = Used in gas cylinders in homes.

Butane = Sold in blue cylinders as ‘camping gaz’. Sold in refill cylinders for portable gas appliances.

Octane = A component of petrol.

What hydrocarbons are saturated?

Hydrocarbons with only single bonds between the carbon atoms are said to be saturated.

This means that the current hydrocarbons we know that are saturated are :

• Alkanes

• Cycloalkanes

• Alcohols

What is the general formula of Alkenes?

CnH2n

All alkenes end in -ene.

What is the shortened structural formula and the ( molecular ) formula for ethene?

Shortened structural formula = CH(2)=CH(2)

( Molecular ) Formula = C(2)H(4)

What hydrocarbons are unsaturated?

Hydrocarbons with a double bond between two carbon atoms are said to be unsaturated.

Some examples of the hydrocarbons we know that are unsaturated are :

• Alkenes

• Carboxylic Acids

What is a homologous series?

A homologous series is a family of compounds which have the same general formula and similar chemical properties.

What is the general formula for Cycloalkanes?

CnH2n

All Cycloalkanes end start with cyclo- and end with -ane.

What is the shortened structural formula and the ( molecular ) formula of cyclopropane?

Shortened structural formula = CH(2)/CH(2)\CH(2)

( Molecular ) Formula = C(3)H(6)

What is the reaction between bromine water with saturated and unsaturated hydrocarbons?

Unsaturated hydrocarbons decolourise bromine water quickly.

Saturated hydrocarbons do not decolourise bromine water quickly.

Explain an addition reaction.

The reaction between an alkene and bromine water.

Explain a substitution reaction.

This is when a bromine atom replaces one of the hydrogen atoms in a hydrocarbon.

What is hydrogenation and hydration?

When hydrogen is added to an alkene to produce and alkane, this is called hydrogenation.

When water is added to an alkene to produce an alcohol, this is called hydration.

What is ( Catalytic ) cracking?

( Catalytic ) cracking is the process used to break up large hydrocarbon molecules, for which there is little demand for, into smaller molecules for which there is higher demand. Unsaturated molecules are also formed in the process.

What are the rules for naming branched chain alkanes?

1. Look for the longest continuous chain of carbon atoms and name it after the alkanes with the same number of carbon atoms.

2. Number the carbon atoms from the end of the chain nearer the branch.

3. Name the branch(es) and show the position(s) of the branch(es) on the chain using the appropriate number

4. If there is more than one type of branch (e.g a methyl and an ethyl group) they should be given in alphabetical order, even if that means that the position numbers are not in numerical order.

5. If there is a halogen (group 7) atom on the carbon chain it can also be named as a branch using the prefixes -fluoro, -chloro, -bromo and -iodo.

What are the rules for naming branched chain alkenes?

1. Look for the longest continuous chain of carbon atoms containing the double bond and name it after the alkene with the same amount of carbon atoms.

2. Number the carbon atoms from the end of the chain nearer the double bond and indicate the position of the double bond by placing a number before the -ene in the alkene name.

3. Name the branch(es) and show the position(s) of the branch(es) on the chain using the appropriate number. You must still use the numbering direction that gives the double bond the lowest number, even if the branches end up with a higher number.

What is an Isomer?

Isomers are molecules which have the same molecular formulae, but different structural formulae.

What is the ending for alcohol hydrocarbons?

The ending for alcohol hydrocarbons is = -anol

What is the shortened structural formula and the ( molecular ) formula for ethanol?

Shortened structural formula = CH(3)OH

( Molecular ) Formula = C(2)H(6)O or C(2)H(5)OH

Some uses of alcohol are =

• Some alcohol are miscible in water and dissolve easily.

• Alcohols are very good solvents, and can be used in screen wipes.

• Alcohol or a solution of alcohol in water has a lower freezing point than water alone and can be used as an anti-freeze or screen wash for windscreens.

• Above a certain concentration alcohol will kill bacteria used in hand gel and disinfectant wipes.

• They are highly flammable and burn efficiently with clean flames. They can be using as fuel or in drag racing and speedway.

• They perform complete combustion extremely well.

What do carboxylic acid hydrocarbons end in?

They have an ending of = -anoic acid.

What is the shortened structural formula of ethanoic acid?

Shortened structural formula = CHOOH

What are the rules for naming alcohols?

1. Look for the longest continuous chain of carbon atoms containing the hydroxyl group and name it after the alkane with the same Humber of carbon atoms, but using -anol as the ending instead of -ane.

2. Number the carbon atoms from the end of the chain nearer the hydroxyl group and indicate the position of the hydroxyl group by placing a number before the -ol in the alchohol name.

3. Name the branch(es) and show the position(s) of the branch(es) on the chain using the appropriate number. You must still use the numbering direction that gives the hydroxyl group the lowest number, even if the branches end up with a higher number.

What are the rules for naming Cycloalkanes?

1. The ring in the Cycloalkanes is given the correct name according to the number of carbon atoms in the ring.

2. It there is only one branch on the ring it does not need a position number, the name of the branch is simply added before the Cycloalkanes name.

3. If there is more than one branch simply chose a branch to number as ‘1’ (if there are different names of branches, ‘1’ should be the earliest in the alphabetical order) and then count round the ring (in either clockwise or anticlockwise direction) in order to give the other branches as low numbers as possible.

Some uses of carboxylic acids are =

• Methanoic, ethanoic, propanoic, and butanoic acid are miscible in water.

• Carboxylic acids have very strong smells.

• Vinegar is ethanoic acid.

• Vinegar can be used to preserve foods by pickling them.

• Vinegar can be used to clean in households.

What is an Ester?

An ester is when an alcohol and a carboxylic acid react together to produce a new substance.

What are some uses of esters?

• They are very good solvents and are used as industrial solvents.

• Esters have very strong, fruity smells and are often using in food flavouring and fragrance.