Alcohol Production - Industrial vs Fermentation

Industrial


Advantages
- The process can be run continually
- the reaction is reversible
- produces 100% percentage yield

Disadvantages
-there is a finite resource
-the process requires a large amount of energy

Hydration of Ethene

Advantages
- It creates useful by products such as acids used to make some food
- requires little energy

Disadvantages
-zymase stops working at 14% alcohol concentration thus limiting concentration of ethanol
-if oxygen enters the system, the products may become toxic

3.8 describe the addition reaction of alkenes with bromine, including the decolourising of bromine water as a test for alkenes

1) ethene + bromine water -> dibromoethane
2)
photo is in omers phone, havent received it yet
3)Explain the observations
It turns from red/brown to colourless. This is because the concentration of the bromine reactant decreases while the concentration of the product decreases (colourless).
4) Why does this reaction not need a catalyst?
It does not need a catalyst because ethane contains an unsaturated carbon-carbon double bond which is highly reactive and can be broken down without the influence of a catalyst.
5)What type of reaction is this called?
Addition reaction
6)Explain why this reaction is useful
This reaction is useful because it allows you distinguish between alkane and alkene using a chemical test. 

3.6 & 3.7 Recall that alkenes have the general formula CNH2N

Take a photo of it and upload to your blog (see sample below)

4. What is the general formula for alkenes?
CNH2N

5. Describe and explain the trend in boiling point
The boiling point increases as there stronger intermolecular forces that require more energy to be broken

6. Explain why there is no such compound as methene
To be classified as an alkene it requires at least one double bond

7. How do you quickly identify from the displayed formula that the hydrocarbon is unsaturated?
Check the general formula that it is not CNH2N+2(i.e. does not only include single bonds)

3.5 I can recall the reaction of methane and bromine

       Alkanes react with bromine in the presence of UV light

·         Explain why this condition is necessary

UV light is needed to supply the energy to break the covalent bonds between hydrogen and carbon

3.       What is this type of reaction called

substitution reaction

4.       State and explain the observations

It would turn from brown to colourless. This is because the concentration of the brown bromine molecule decreases while the concentrations of the product increase (colourless).

5.       Draw the displayed formula of the reaction between methane and bromine (upload a photo)

6.       Write out a balanced (with state symbols) the reaction between ethane and chlorine
C₂H_6 (l)+ Cl_2(g) -> C₂H₅Cl(l) + Hcl (aq)

7.       State and explain the observations in this chemical reaction

It turns from green to colourless. The reactants (chlorine) are green and the products (ethanechloride and hydrochloric acid) are colourless. This is a substitution reaction where the concentration of  the green chlorine molecule decreases and the colourless products increase.

3.4 Recall the products of the complete and incomplete combustion of alkenes

1.       Saturated hydrocarbons are called alkanes

2.       Small chain alkanes are used as fuels

3.       The reaction is called combustion

4.       The word equation for  this chemical reaction is :

fuel (alkane) + oxygen → water + carbon dioxide+ ENERGY (heat, light, sound)

5.       If there is insufficient oxygen then the word equation is:

fuel (alkane) + oxygen → carbon monoxide + water + ENERGY (heat, light, sound)

6.       The problem with this reaction is that carbon monoxide is produced this gas is toxic to the human body (see objective 5.11)

7.       Where can you find incomplete combustion?

In car engines or in your house when you burn fire.

8.       What is used to reduce the harmful products from incomplete combustion?

Use a catalytic converter to convert CO to CO₂9.       During incomplete combustion a smoky flame is often seen, explain this observation

Extn: write a balanced equation (with state symbols) for the combustion of propane gas
This is soot which is formed by unburnt carbon

C₃H₈  + 5O_2    à  3CO₂ + 4H₂O

3.2 and 3.3 I can recall the general formula and the displayed formulae for alkenes

NOTE: answers are in white

What is the general formula for alkanes?

C(n)H(2n)

Describe and explain the trend in boiling point.

The boiling point increases as you go down the group. This is because the molecules get larger and their are more intermolecular forces to break.

  

3.1 I can explain terms homologous series, hydrocarbon, saturated, unsaturated, general formula, and isomerism

NOTE: answers in white

Term	Definition	Example
Homologous series	a family of hydrocarbons with the same general formula	alkanes
Hydrocarbon	a compound containing only carbon and hydrogen	crude oil
Saturated hydrocarbon	a hydrocarbon which only contains single bonds	alkane
Unsaturated hydrocarbon	a hydrocarbon that contains at least one double bond	alkene
General formula	a mathematical equation that shows the ratio of the different atoms (i.e. carbon and hydrogen)	C(n)H(2n)
Isomerism	Hydrocarbons with the same general formula but with a different structure