Introduction To Organic Chem

Question 1

Organic Chemistry is all about what?

Answer 1

Carbon compounds

Question 2

What does the general formula of organic compounds show you and give examples

Answer 2

An algebraic formula that can describe any member of a family of compounds. E.g alcohols = CnH2n+1OH

Question 3

What does the empirical formula of organic compounds show you and give examples

Answer 3

The simplest ratio of atoms of each element in a compound. E.g ethane C2H6 = CH3

Question 4

What does the molecular formula of organic compounds show you and give examples

Answer 4

The actual number of atoms of each element in a molecule e.g C4H10 (butane)

Question 5

What does the structural formula of organic compounds show you and give examples

Answer 5

Show the atoms carbon by carbon with the attached hydrogens and functional groups. E.g CH3CH2CH2CH2OH

Question 6

What does the skeletal formula of organic compounds show you and give examples

Answer 6

Shows the bonds of the carbon skeleton only with functional groups. Hydrogen and carbon atoms are not shown which makes it easier to draw cyclic hydrocarbons

Question 7

What does displayed formula of organic compounds show you and give examples

Answer 7

Shows how all the atoms are arranged and all the bonds between them, see physical flash cards for examples

Question 8

What is a homologous series?

Answer 8

A sequence of compounds with the same functional group and similar chemical properties

Question 9

What is the general formula for alkanes

Answer 9

CnH2n+2

Question 10

Name 8 homologous series and their suffixes/ prefixes

Answer 10

• Alkanes-ane
• Alkenes- ene
• Carboxylic acids- oic acid
• Branched alkanes- alkyl
• Halogenoalkanes- fluoro/chloro/Bromo/iodo
•alcohols- ol
• aldehydes- al
• Ketones- one

Question 11

Give the steps for naming organic compounds

Answer 11

• Count the longest consecutive carbon chain and deduce the prefix
• Look for the functional group and decide the suffix
• Number the functional group (if required)
• look for additional groups e.g CH3: methyl, ethyl,propyl
• Number the additional things
• Put the name together
• Di, tri, tetra

Question 12

How has IUPAC naming contributed to organic compounds

Answer 12

Scientific ideas can be communicated across the globe more effectively.

Question 13

Give the functional group for alkanes, alkanes, Haloalkenes, alcohols, aldehydes, ketones, Carboxylic acids

Answer 13

• C-H
• C=C
• C-X x, is any halogen
• CHO
• C(O)
• COOH

Question 14

How many bonds does a carbon atom have in alkane so that means they are what?

Answer 14

4 single bonds so they are saturated

Question 15

Draw the structure of cyclohexane

Answer 15

Check physical flash cards to see if you got it right

Question 16

What is another word for petroleum

Answer 16

Crude oil

Question 17

What type of hydrocarbons are found in petroleum

Answer 17

Alkanes

Question 18

What is the process of separating crude oil?

Answer 18

Fractional distillation

Question 19

Describe in 4 steps how fractional distillation works

Answer 19

• Crude oil is vaporized at 350*C

• Vaporized crude oil goes into the fractionating column and rises up the trays. Larger hydrocarbons don’t vaporize due to high boiling points so the run to the bottom of the column to form a gooey residue.

• As vapour rises up the column it gets cooler. Because alkanes have different chain lengths which lead to different boiling points so each faction condenses at different columns

• Hydrocarbons with the lowest hydrocarbons don’t condense, they’re drawn off as gases at the top

Question 20

What is cracking?

Answer 20

Cracking is breaking long-chain alkanes into smaller hydrocarbons. It involves breaking c-c bonds

Question 21

Why are less popular heavier fractions cracked?

Answer 21

Because they are not high in demand and therefore less valuable

Question 22

What are the two types of cracking

Answer 22

Thermal and catalytic

Question 23

Describe thermal cracking

Answer 23

• High temperature and pressure
• Produces lots of alkenes and few alkanes
• Alkenes are used to make polymer e.g plastics and polyethene made from ethene
  >1000C at 70 atm

Question 24

Describe catalytic cracking

Answer 24

• Uses a zeolite catalyst at a slight pressure and high temperature, 450C
• Produces aromatic hydrocarbons and motor fuels

*Using a catalyst lowers costs cause it speeds up the rate of reaction saving time since it can be done at low pressure and temperature

Question 25

What does burning alkanes lead to?

Answer 25

Pollutants

Question 26

What products are formed during complete combustion

Answer 26

Carbon dioxide and water, a blue flame

Question 27

What causes incomplete combustion

Answer 27

Less oxygen to react, orange and smoky flame due to pure carbon burning red hot

Question 28

Why and how is carbon monoxide harmful as a result of incomplete combustion

Answer 28

• It is poisonous • Binds to the same site on haemoglobin molecules as oxygen molecules so oxygen can’t be carried around the body • It can be removed by catalytic converters in cars

Question 29

Why is carbon harmful as a product of incomplete combustion

Answer 29

• Causes breathing problems • Can also build up in engines

Question 30

Describe how burning fossil fuels contributes to global warming

Answer 30

• Produces green house gases • Green house gases absorb infrared energy (heat). They emit some energy back towards the earth, making the earth warmer • This is known as global warming

Question 31

How is oxides of nitrogen (NO) produced?

Answer 31

When high pressure and temperature cause nitrogen and is then atoms from the air to react together

Question 32

Describe how ground level ozone is formed and how this affects people

Answer 32

• Hydrocarbons and nitrogen oxides react in the presence of sunlight • This is a component of smug • Form ground level ozone which affects peoples eyes • Aggravates respiratory problems and causes lung damage • Catalytic converters remove unburnt hydrocarbons and oxides of nitrogen from exhaust

Question 33

How is acid rain formed and what are its effects

Answer 33

• When burnt fossil fuels contain sulfur • Sulfur reacts to form sulfur dioxide gas • In the atmosphere, it dissolves in the moisture and is converted to sulfuric acid which causes acid rain • Acid rain destroys trees and vegetation, corroding buildings and statues and kills fish in lakes

Question 34

How can sulfur dioxide be removed

Answer 34

Powdered calcium carbonate or calcium oxide is mixed with water to make an alkaline slurry. When flue gas mix with alkaline slurry, acidic sulfur oxide reacts with calcium compounds to form harmless salt, calcium sulphite

Question 35

Give examples of catalytic converters

Answer 35

Platinum and rhodium

Question 36

What are the problems of incomplete combustion of long chain alkanes and why

Answer 36

Longer chain alkanes require more oxygen to combust completely

Question 37

Draw the displayed formula from of 3-fluoro-2,2-dimethylpentane

Answer 37

Check physical flashcards for answers

Question 38

Define fractional distillation, thermal cracking and addition polymerisation

Answer 38

• Fractional distillation: separated into mixtures of compounds with similar boiling points/similar sized molecules • Thermal Cracking: To make alkenes/propene/shorter molecules • Addition polymerisation: molecules joined together or to produce a long chain molecule

Question 39

Plantinum, palladium and rhodium are metals used inside catalytic converters. A very thin layer of metals is used on a honeycomb ceramic support. Explain why a thin layer is used in this way

Answer 39

To provide a large surface area to give the catalyst a large surface area to volume ratio

Question 40

How to name molecules

Answer 40

• Always draw the molecule out • Always count the longest carbon chain

Question 41

What is the use of nitrogen monoxide in catalytic converters

Answer 41

convert toxic gas such as carbon monoxide to carbon dioxide and nitrogen monoxide turns to nitrogen gas

Question 42

Safety signs on the fuselage of the helicopter state that the air inlets to the engine need to be cleaned out regularly. Suggest how this partial blockage might affect the performance of the helicopter engine.

Answer 42

Less energy given out by the fuel / engine is less powerful / less efficient / needs to burn more fuel to get the same energy / increased costs due to need to use more fuel