Chem Crude Oil

Question 0

What is a mixture?

Answer 0

A blend of 2 or more substances that are not chemically combined and can be separated by physical means.

Question 1

What is crude oil?

Answer 1

Fossil fuel, made naturally from dead plants and animals living in ancient seas millions of years ago, non renewable

Question 2

What is a compound?

Answer 2

A substance that contains 2 or more elements chemically combined in a fixed ratio.

Question 3

What is crude oil composed of?

Answer 3

Hydrogen and carbon. May also contain sulphur, nitrogen and oxygen and various trace elements.
Composition depends on place of origin!

Question 4

Is crude oil useful in its natural state?

Answer 4

No. Must be separated and refined.

Question 5

How can crude oil be made useful?

Answer 5

Separate compounds into fractions.

Each fraction contains a mix of compounds with similar no. carbons.

Question 6

How can crude oil be separated?

Answer 6

Fractional distillation in a fractionating column.

Hydro carbons separated according to boiling points.

Question 7

What happens during fractional distillation?

Answer 7

Oil heated to 370 oC
Pumped into bottom of column where it vapourises.
Bottom of column very hot, much cooler at top
Vapourised oil rises, cools and condenses.

Question 8

What happens in the column?

Answer 8

Heavy fractions(large) high boiling point and condense at bottom of column
Light fractions (small) low boiling point condense further up the column

Question 9

What trends can be seen between length of hydrocarbon and boiling points?

Answer 9

Larger hydrocarbon:
Higher boiling point
Greater no. of carbons

Question 10

What are the physical properties of the fractions?

Answer 10

The larger the hydrocarbon :
More carbon atoms in the molecule
Higher boiling point
Darker in colour they become
Higher viscosity and less flammable they become

Question 11

List the different fractions.

Answer 11

L= liquid petroleum gas P=petrol N=naphtha K= kerosene D= diesel
F=fuel oil L= lubricating oil B= bitumen
Little peppa never knew daddy’s friend liked books.

Question 12

List in order the process of refining crude oil.

Answer 12

1. extracted from oil fields 2. Heated in fractionating column 3.liquid evaporates and vapour condenses at diff temps 4.fraction with highest bp comes at bottom of tower 5. Fraction with lowest bp comes at top of column 6. Light fractions, usually liquids with low bp come out first
2. This process produces range of oils and fuels.

Question 13

What is an Alkane?

Answer 13

Alkanes are saturated hydrocarbons (ends in “ane”)

Single covalent bonds

Question 14

What are the first 4 hydrocarbons?

Answer 14

Methane ethane propane butane ( monkeys eat peanut butter)

Rest follow geometric shapes

Question 15

What is the chemical formula for an Alkane?

Answer 15

CnH2n + 2

Question 16

What are the physical properties of an Alkane?

Answer 16

Change physical properties as the number of hydrocarbons increase
First 4 gases
Next 12 liquids
Rest solids
Nearly all alkanes have densities less than water

Question 17

What happens to the boiling point and melting as the carbon chain increases?

Answer 17

Boiling and melting point increase also

Question 18

Alkane + oxygen =

Answer 18

During the combustion reaction they produce water and co2

Eg. Methane +oxygen= water + carbon dioxide

Question 19

What happens to alkanes if there is a poor supply of air?

Answer 19

Carbon monoxide is produced when an Alkane combusts incompletely.

Question 20

What is cracking?

Answer 20

Breaking large hydrocarbons into smaller more useful ones. High temp, high pressure and a catalyst is required. Done in a cracker.

Question 21

What type of reaction happens during cracking?

Answer 21

Thermal decomposition reaction

Forms Alkane and alkene

Question 22

What is an alkene?

Answer 22

Alkene are hydrocarbons containing a carbon carbon double bond as well as single bonds.

Question 23

What does unsaturated mean?

Answer 23

A double bond between the Carbon atoms.

Extra bond can be broken and another such as hydrogen added.

Question 24

What are alkanes used for?

Answer 24

Extremely reactive and very important in chemical industry eg. Plastics

Question 25

What is the test to determine an Alkane or alkene?

Answer 25

Mix with bromine water
Alkene- unsaturated turns colourless. Double bonds break
Alkane - saturated stays the same colour orange

Question 26

What is addition polymerisation?

Answer 26

It’s the joining together of alkene molecules. High temp, high pressure and catalyst used to break double bonds to make more molecules.
Eg. Poly(e) thene