organic chem

Question 1

what type of organic reaction occurs when chlorine and methane are mixed in the presence of uv light?

Answer 1

substitution

Question 2

why is methanol very soluble in water?

Answer 2

because it is polar

Question 3

name or give the formula for a reagant that could be used to oxidise a sample of methanol

Answer 3

sodium or potassium dichromate

Question 4

define octane number?

Answer 4

the measure of the tendency of a fuel to resist knocking

Question 5

define auto ignition?

Answer 5

the premature ignition of the petrol air mixture before normal ignition of the mixture

Question 6

what compound has an octane number of 100?

Answer 6

2-2-4 trimethylpentane

Question 7

what compound has an octane number of 0

Answer 7

heptane

Question 8

what are heptane and 2-2-4 trimethylpentane called?

Answer 8

reference hydrocarbons

Question 9

how can the octane number of a fuel be measured?

Answer 9

by comparing its performance with known mixtures of heptan and 2-2-4 trimethyl pentane

Question 10

what is an aliphatic compound?

Answer 10

an organic compound that conssits of open chain carbon atoms and closed chain compounds .

Question 11

what do we observe when preparing ethyne?

Answer 11

1 fizzing takes place in the flask and a white solid is formed
2 the flask gets warm
3 bubbles of gas begin collecting in the jar

Question 12

when we burn ethyne what is observed?

Answer 12

a bright smoky flame with alot of soot being formed due to unburnt carbon

Question 13

when we add bromine water/ kmno4 to ethyne what color change is observed?

Answer 13

from red to colourless

Question 14

name 4 common ways of increasing the octane number of petrol?

Answer 14

isomerisation , catalytic cracking , dehydrocyclisation , adding oxygenates

Question 15

define polymer?

Answer 15

long chain molecules made by joining many small molecules

Question 16

what is an addition reaction

Answer 16

one in which two or more molecules react togethor to form a single molecule

Question 17

redox reaction

Answer 17

when a primary alcohol reacts with an oxidising agent

Question 17

define organic synthesis

Answer 17

the process of making organic compounds from simpler starting molecules

Question 17

first step of pvc synthesis?

Answer 17

in the first step ethene reacts with chlorine making 1-2 dichloroethane

Question 18

second step of pvc synthesis

Answer 18

in the second step 1-2 dichloroethane is subjucted to thermal cracking removing an hcl molecule and leaving us with vinyl chloride

Question 19

State boyles law

Answer 19

Boyles law states that at constant temperatuee the volume of a fixed amount of gas is inversely proportional to its pressure

Question 20

State charles law

Answer 20

Charles law states that at constant pressure the volume of a fixed amount of gas is directly proportional to its temperature on the kelvin scale

Question 21

The molecular formula

Answer 21

The molecular formula for a compound shows the number and type of each atom present in the molecule

Question 22

Empirical formula

Answer 22

The formula showing the simplest whole number ratio of the numbers of diff atoms present in a molecule

Question 23

Define molarity

Answer 23

The number of moles per litre of solution

Question 24

Define a salt

Answer 24

The substance formed when the hydrogen ion in am acid is replaced by a metal

Question 25

Arrhenius definition of a strong acid

Answer 25

A substance that almost completely dissociates in water to give hydrogen ions

Question 26

Arrhenius definition of a weak acid

Answer 26

A substamce that only partially dissociates in water to give hydrogen ions

Question 27

Arrhenius definition of a base

Answer 27

A substance that dissacosiates in water to give oh ions

Question 28

Step 1 in finding water of crystillisation in hydrated sodium carbonate

Answer 28

The pipette burette and conical flask are washed with deionised water

Question 29

Step 2 in finding water of crystillisation in sodium catbonate

Answer 29

About 5g of sodium carbonate crystals are weighed out on a clock glass

Question 30

Step 3 of water of crystillisation in sodium carbonate

Answer 30

The crystals are dissolved in water and transferred to a 250cm3 volumetric flask

Question 31

What is a strong acid?

Answer 31

A good proton donor

Question 32

What is a strong base?

Answer 32

A strong base is a good proton acceptor

Question 33

Define electrolysis

Answer 33

The use of electricity to bring about a chemical reaction

Question 34

Define elctrolyte

Answer 34

A compound which when molten or dissolved in water will conduct electricity

Question 35

Define electroplating?

Answer 35

A process where electrolyiss is used to put a layer of one metal on the surface of another

Question 36

What is a galvanic cell?

Answer 36

A cell in which a chemical reaction results in the production of current

Question 37

What is an elimination reaction?

Answer 37

The reverse of an addition reaction removing a substrate

Question 38

Hess law

Answer 38

States that if a chemical reaction takes place in a number of stages the sum of the heat changes in the seperate stages is equal to if it was done in one stage

Question 39

Define condensation reaction?

Answer 39

A reaction in which two molecules combine to form a larger molecule with the loss of a smaller molecule

Question 40

Define steam distillation

Answer 40

A seperation process used to isolate compounds at temperatures below their decomposition temperature

Question 41

Substitution reaction definition

Answer 41

A reaction in which an atom or group of atoms is replaced by another atom or group of atoms

Question 42

To prepare a sample of soap key steps

Answer 42

1 Lard or sunflower oil is put in a quickfit flask

2 sodium hydroxide and ethanol are added to the flask

3 some anti bumping chips are added

Question 43

To study the reaction of ethanoic acid with sodium carbonate

Answer 43

1 Some sodium catbonate powder is placed in a boiling tube

2 some ethanoic acid solution is added to the sodium carbonate powder