3.8 I can describe the reaction between alkenes and bromine

1.       Write the word equation showing the reaction between ethene and bromine water
      ethane + bromine water --> dibromoethane
2.       Draw the displayed formula of the reaction above

3.       Explain the observations

It Bromine solution turns from Orange/Brown into colourless, this is because the concentration of bromine is decreasing and there is an increase of the product which is dibromoethane which is colourless.

4.       Why does this reaction not need a catalyst?

This reaction does not need a catalyst because ethene is unsaturated and the carbon carbon double bonds can be broken meaning they are reactive.

5.       What type of reaction is this called?

This reaction is addition reaction.

6.       Explain why this reaction is useful

To distinguish between alkenes and alkanes,  a chemical test to see if it has a double bond.

'3.6 and 3.7 I can recall the general formula and displayed formulae of alkenes

4. What is the general formula for alkenes?

CNH2N

5. Describe and explain the trend in boiling point

As the boiling point increases there are stronger inter molecular forces that need more energy to be broken.

6. Explain why there is no such compound as methene

There is no such compound as methene because to be classed as an alkene the compound needs to have a double bond when is not possible in methene because it only has one carbon.

7. How do you quickly identify from the displayed formula that the hydrocarbon is unsaturated?

This is done by looking for a carbon double bond which indicates it is unsaturated.

3.5 I can recall the reaction of methane and bromine

   1.    Alkanes react with bromine in the presence of UV light.  Explain why this condition is necessary

UV light is needed to break the bonds between of bromine, because UV light provides the energy to break the bonds.

2.What is this type of reaction called?

Substitution Reaction

3. State and explain the observations

The Brown Bromine slowly looses its color and becomes colorless this is because it is slowly becoming hydrogen Bromide 

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

C2H6(g) + Cl2(g) -->C2H5Cl(g) +HCl(g)

7.       State and explain the observations in this chemical reaction

The colour changes from a yellow to colourless this is because the chlorine reacts with ethane to form a colourless product, this is a substitution reaction.