[Part 2]- C9- crude oil and hydrocarbons ⛽️

Question 1

What is fractional distillationO ?

Hint: components in a chemical mixture

Answer 1

• fractional distillation, is a process by which components in a chemical mixture are separated into fractions [different parts], according to their different boiling points.

Question 2

How is crude oil separated ?

Answer 2

• crude oil is separated by fractional distillation.
• in fractional distillation, crude oil is separated into fractions.

Question 3

What is a fraction ?

Hint: similar number

Answer 3

• a fraction, contains hydrocarbons with a similar number of carbon atoms
• [and some fractions may be used as fuels]

Question 4

What are the stages of fractional distillation ? [5]

Hint: high temperature, evaporate, rises up, boiling point, removed

Answer 4

• crude oil is vaporised, and turned into a gas by heating
• and the hydrocarbon gases will enter the fractionating column, and then rise up the fractionating column
• as hydrocarbon gases rise up the column, they will cool down and once they reach their boiling point in the fractionating column, they will condense
• and the hydrocarbon fraction is then collected

Question 5

Where are long chain hydrocarbons removed from the fractionating column ?

Hint: hot

Answer 5

• because very long chain hydrocarbons have very high boiling points, long chain hydrocarbons are removed from the bottom of the fractionating column [which is hot]

Question 6

How are short chain hydrocarbons removed from the fractionating column ?

Answer 6

• ; as very short chain hydrocarbons have very low boiling points, they are removed from the top of the fractionating column. [which is cool]
• this means, they don’t condense and are therefore removed as gases

Question 7

What are an example of fractions, that are used as fuels ?

Answer 7

• petrol and diesel is used to fuel cars
• kerosene is used as jet fuel
• ; heavy fuel oil is used to power ships, and liquified petroleum gas is used in camping stoves

Question 8

• Fill in the gaps: some _________ are used as feedstock, for the petrochemical industry

Answer 8

• Fill in the gaps: some fractions are used as feedstock, for the petrochemical industry

Question 9

What is a feedstock ?

Answer 9

• a feedstock, is a chemical that is used to make other chemicals

Question 10

What are some examples of feedstock ?

Answer 10

• solvents
• lubricants
• detergents
• and, polymers

Question 11

What covalent bonds do alkanes have ?

Answer 11

• alkanes, only have single covalent bonds between the carbon atoms

Question 12

What is cracking ?

Answer 12

• cracking, is when a long chain hydrocarbon molecules such as alkanes, are broken down [cracked] to produce a shorter chain molecule

Question 13

What are the conditions for catalytic cracking ?

Answer 13

• in catalytic cracking, a high temperature and catalyst is used
• this is done at an oil refinery, in steel vessels known as crackers. In the cracker, a heavy fraction distilled from crude oil is heated to vaporise the hydrocarbons, and is then passed over a hot catalyst at 500*c

Question 14

RECAP: What is a catalyst ?

Answer 14

• a catalyst, is a substance that increases [speeds up] the rate of chemical reactions; it remains chemically unchanged itself, at the end of the reaction.

Question 15

What are the conditions for steam cracking ?

Answer 15

• in steam cracking, high temperatures and steam is used

Question 16

What is an alkene ?

Hint: molecule

Answer 16

• an alkene, is a molecule with a double covalent bond between two carbon atoms, which is more reactive than an alkane

Question 17

Why are alkenes useful ?

Hint: polymers

Answer 17

• alkenes, are used to make chemicals known as polymers
• alkenes are used as a starting material for useful chemicals

Question 18

• Fill in the gaps: since alkenes are more reactive than _______, they can be used to test for alkenes

Answer 18

• since alkenes are more reactive than alkanes, they can be used to test for alkenes

Question 19

What is the test for alkenes ?

Answer 19

• alkenes are tested with [orange] bromine water and then shaked.
• if the bromine water turns colourless, an alkene is present

Question 20

Why are the products of cracking useful ?

Hint: high demand

Answer 20

• the products of cracking are useful because, there is a high demand for short chain molecules which can be used as fuel

Question 21

Describe the process for steam cracking

Answer 21

• steam cracking is done at an oil refinery, in steel vessels known as crackers.
• In the cracker, a heavy fraction distilled from crude oil is heated to vaporise the hydrocarbons
• and the hydrocarbon vapour is mixed with steam, and heated to a very high temperature

Question 22

Describe the process of catalytic cracking

Answer 22

• in catalytic cracking, a high temperature and catalyst is used
• this is done at an oil refinery, in steel vessels known as crackers.
• In the cracker, a heavy fraction distilled from crude oil is heated to vaporise the hydrocarbons, and is then passed over a hot catalyst at 500*c

Question 23

What is steam cracking ?

Answer 23

• steam cracking is when hydrocarbons are cracked, and broken down into shorter hydrocarbon molecules by mixing them with steam and heating them to a high temperature