C10 - Organic Reactions Flashcards
What do organic compounds form the basis of?
All living things
What atoms do all organic molecules contain?
Carbon atoms.
Carbon atoms form the backbone of all organic molecules.
What is a ‘functional group’?
The area of a molecule that is reactive and gives a ‘family’ of organic molecules its distinctive reaction characteristics.
What is the functional group in alkenes?
The ‘C==C’ double carbon bond.
What do chemists call a ‘family’ of organic compounds with the same functional group?
A homologous series.
What are some examples of homologous series?
Alkanes - Methane, Ethane, Propane, Butane, Pentane
Alkenes - Ethene, Propene, Butene, Pentene
Why are Alkenes very reactive?
Because of the ‘C==C’ double carbon bond.
Why are Alkenes rarely burned?
Alkenes release far less energy than alkanes.
Alkenes tend to undergo incomplete combustion - so they burn with a smoky flame.
What are alkenes useful for making/producing?
Alkenes are so valuable in making polymers and plastics.
What type of reaction do alkenes undergo?
Addition Reactions
What happens in an addition reaction of an alkene?
The C==C double carbon bond undergoes the addition.
The C=C double carbon bond becomes a single C–C bond, and other atoms join onto the 2 carbon atoms.
What is the general formula/template for an addition reaction?
General Formula:
X Y
| | | |
C==C + X—Y —> —C—C—
| | | |
How do alkenes react with the halogens? (C2, Br2, I2) Give an example:
- The C==C double bond becomes a single bond.
- The number of hydrogen atoms stays the same.
- The 2 halogen atoms are added on to the displayed formula.
Example:
Ethene + Bromine —> *Dibromoethane
C2H4 + Br2 —> C2H4Br2
*Dibromoethane is colourless because of the presence of bromine (think about alkene test in orange coloured bromine water).
How do alkenes react with hydrogen, (H2)? What conditions must the reaction be under? Give an example:
-Alkenes react with hydrogen (H2) to produce an alkane - due to the fact that the maximum number of hydrogen atoms are now attached.
Conditions:
-The reaction must be at a temperature of 150°C with a NICKEL CATALYST.
-This process of hydrogenising alkenes is used to make margarine.
Example:
Ethene + Hydrogen —> Ethane
C2H4 + H2 —> C2H6
How do alkenes react with water (steam)? What conditions must the reaction be under? Give an example:
-Alkenes make alcohols when reacted with water (steam).
Conditions:
-There must be a high temperature and a concentrated PHOSPHORIC ACID CATALYST.
- Displayed Formula:
- The alkene gains 2H’s and an O (H2O) from the water. So you draw an O—H as well as an H on its own, onto the hydrocarbon.
Example:
Ethene + Steam —> Ethanol
C2H4 + H2O —> C2H5OH
What functional group does the homologous series of alcohols contain?
The ‘OH’ functional group.
This helps you to recognise an alcohol.
What is the general formula for an alcohol?
(CnH2n+1)OH
What are the the first 4 alcohols and there chemical formula?
Methanol, CH3OH
Ethanol, C2H5OH
Propanol, C3H7OH
Butanol, C4H9OH
Which alcohol is ‘common alcohol’ used in drinks?
Ethanol, C2H5OH
What does the displayed formula of an alcohol look like?
It looks like a hydrocarbon except on one of the branches, there is an O connected to an H:
Methanol:
H
|
H — C — OH
|
H
What molecules are alcohols definitely not examples of?
They are NOT Hydrocarbons.
They don’t have just hydrogen and carbon atoms in their bonds.
What functional group does the homologous series of carboxylic acids contain?
The ‘COOH’ functional group.
What is the general formula for carboxylic acids?
Cn-1H2n-1COOH (or CnH2nO2)
E.g Ethanoic Acid = 1C, 3H + COOH gives you CH3COOH.
What are the first 4 carboxylic acids and what are there chemical formulas?
Methanoic Acid, HCOOH (CH2O2)
Ethanoic Acid, CH3COOH
Propanoic Acid, CH3CH2COOH
Butanoic Acid, CH3CH2CH2COOH
*Essentially you start with HCOOH (CH2O2), and you add CH3. Then you add CH2 each time.
