Fuels and Heats of Reactions

Question 1

Fractional Distillation is

Answer 1

The method that heats crude oil and separates the materials by their boiling points

Question 2

What are the boiling points of crude oil called

Answer 2

Fractions

Question 3

What is added to odourless gases like methane, ethane, propane and butane and why

Answer 3

Since they are odourless sulphurous Mercaptans are added to scent them for saftey

Question 4

What does LPG stand for, and what are two examples

Answer 4

Liquified Petroleum Gas
(e.g Propane and Butane)

Question 5

What is auto-ignition

Answer 5

It is the premature ignition of petrol-air mixture before normal ignition of the mixture by spark takes place

Question 6

Knocking is when

Answer 6

Pistons vibrate due to auto-ignition

Question 7

The Octane Number is

Answer 7

A measure of the tendency of a fuel to resist knocking

Question 8

What cause Knocking

Answer 8

Straight chain alkanes

Question 9

What do not cause knocking

Answer 9

Branched chained alkanes

Question 10

What is a saturated compound

Answer 10

It is one in which there are only single bonds between the atoms in the molecule

Question 11

What is an unsaturated compound

Answer 11

It is one that contains one or more double or triple bonds between the atoms in the molecule

Question 12

Name the first ten members of the alkane family

Answer 12

Methane- May-CH4
Ethane- Every-C2H6
Propane- Pupil-C3H8
butane- Bloom-C4H10
pentane- Perfectly….
Hextane- Healthy….
Heptane- Happily ….
Octane- On…..
Nonane- No ones …
Decane- Deck…..

Question 13

What are tetrahedral Fuels like Methane

Answer 13

When the bonds between carbon are single the carbon is said to be tetrahedrally bonded

Question 14

What are planar fuels referring to

Answer 14

When a double or triple bond occurs those carbons are described as planar

Question 15

What is a homologous series

Answer 15

A group of compounds of similar chemical property, and method of preparation, differing by a CH2 unit

Question 16

State a use of ethene

Answer 16

It is a ripening agent found in fruit

Question 17

What are aliphatic compounds

Answer 17

Organic compound that consists of open chains of carbon atoms and closed chain compounds that resemble them in chemical properties

Question 18

What are Aromatic compounds

Answer 18

Compounds that contain a benzene ring structure in their molecules

Question 19

What’s Benzene

Answer 19

Molecular formula is C6H6
Discovered by Faraday
Kekule deduced ring structure
Lonsdale confirmed cyclic nature

Question 20

Monovalent

Answer 20

Atoms that are only prepared to give or share electron in order to have a full stable energy level

Question 21

What is the name of the bond benzene has that is described as ‘ a bond and a half’

Answer 21

Intermediate length bonds

Question 22

What is valency of an element

Answer 22

It is the number of atoms of hydrogen or any other monovalent element with which each atom of the element combines

Question 23

How are single bonds formed

Answer 23

The sharing of two electrons by two atoms

Question 24

How are double bonds formed

Answer 24

Two pairs of electrons are shared

Question 25

How are triple bonds formed

Answer 25

Three pairs of electrons are shared

Question 26

What is the head on overlap of two atomic orbitals called

Answer 26

sigma bond

Question 27

What is the side on overlap of two atomic orbitals called

Answer 27

Pi bond

Question 28

single bonds are

Answer 28

Sigma

Question 29

Double bonds are

Answer 29

one sigma one pi

Question 30

triple bonds are

Answer 30

one sigma two pi

Question 31

state three differences between sigma and pi bonds

Answer 31

sigma are caused by head on overlap while pi is caused by side on overlap Sigma bonds are stronger, pi are weaker Sigma bonds are formed first, pi are formed after

Question 32

What type of molecule is benzene

Answer 32

A planar

Question 33

Benzene electrons are not confined to specific carbon atoms, so they are said to be

Answer 33

delocalised

Question 34

Exothermic reaction

Answer 34

Give heat out

Question 35

Endothermic reactions

Answer 35

take heat in

Question 36

The Heat of Reaction

Answer 36

Is the heat change when the number of moles of the reactants indicated in a balanced equation for the reaction, react completely

Question 37

Heat of Combustion

Answer 37

Is the heat change when one mole of the substance is completely burned in excess oxygen

Question 38

What is Bond Energy

Answer 38

It is the energy required to break one mole of covalent bonds and to separate the neutral atoms completely from each other.

Question 39

Heat of Neutralisation

Answer 39

Is the heat change when 1 mole of H+ ions from an acid, reacts with 1 mole of OH ions from the base

Question 40

Heat of Formation

Answer 40

Is the heat change when one mole of a compound in its standard state is formed from its elements in their standard states

Question 41

Catalytic Cracking

Answer 41

Is the breaking down of long chain hydrocarbon molecules into short chain molecules for which there is greater demand

Question 42

Techniques to improve Octane Number

Answer 42

Isomerisation, analytic Cracking, Reforming, Addition of Addictives

Question 43

What is an Isomer

Answer 43

Same molecular formula, but different structural formula