'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
Boiling point is higher up the homogeneous series because more energy is needed to break the strong covalent bonds.

6.       Explain why there is no such compound as methene

There is only one carbon atom and no other carbon atom to share a double bond with.

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

By looking at the structure there should be at least one carbon carbon double bond.

"3.5 I can recall the reaction of methane and bromine"

 1.   Alkanes react with bromine in the presence of UV light.

 2.    Explain why this condition is necessary?
        UV light provides the energy  needed to break the Bromine bonds. 

3.       What is this type of reaction called : Substitution Reaction

4.       State and explain the observations : Brown/Orange (Bromine) and the product (Bromomethane + Hydrogen Bromide) will turn 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

     C2H6(g)+Cl2(g) --> C2H5CL(g)+Hcl(g)

7.       State and explain the observations in this chemical reaction

Yellow (chlorine) turns to a colourless (products are colourless)

--> Bromomethane

"3.4 I can recall the products of complete and incomplete combustion of alkenes"

1.       Saturated hydrocarbons are called Alkane

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 → Water+ Carbon monoxide + ENERGY (heat, light, sound)

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

7.       Where can you find incomplete combustion? In cars

8.       What is used to reduce the harmful products from incomplete combustion? catalytic converter (converts carbon  monoxide --> Carbon dioxide)

9.       During incomplete combustion a smoky flame is often seen, explain this observation

The smoke is the unburnt carbon in the incomplete combustion  which forms soot.

Extn: write a balanced equation (with state symbols) for the combustion of propane gas

C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(l)

"3.2 and 3.3 I can recall the general formula and displayed formulae of alkanes"

3. CnH2+2
4. The more atoms in molecules, the higher the boiling point.

5.    Draw the displayed formula of the three isomers of pentane

Pentane, Butane, Propane, Ethane , Methane

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

Term	Definition	Example
Homologous series	Members of the same series, or family having similar chemical properties.	alkanes, alkenes
Hydrocarbon	A hydrocarbon is a compound containing only hydrogen and carbon.	crude oil, methane, ethane, propane, butane, pentane
Saturated hydrocarbon	Molecules with a  carbon carbon single bond throughout the whole structure	e.g. of Alkanes (Methane)
Unsaturated hydrocarbon	Molecule with a carbon carbon double/triple bond	e.g. of Alkenes (Ethene)
General formula	A mathematical formula to express the number of carbon and hydrogen atoms in a molecule	CnH2n+2 , CnH2n
Isomerism	Molecules having the same formula, but are structured differently.	2,2 Dimethylpropane

"5.13 describe how long-chain alkanes are converted to alkenes and shorter-chain alkanes by catalytic crackling, using silica or alumina as the catalyst and a temperature in the range of 600-700C"

3. A catalyst is a substance which speeds up a chemical reaction. At the end of the reaction, the catalyst is chemically unchanged. 

4. A catalyst is used so we can get more product in a certain time using a suitable catalyst.

5. To speed up reactions and break the bonds

"5.11 recall that in car engines, the temperature reached is high enough to allow nitrogen and oxygen from air to react, forming nitrogen oxides"

Blog Tasks:


a. Write the general equation for the combustion of a fuel
Oxygen+Fuel --> Oxides+water+energy
b. During combustion the nitrogen in air can react to form what gases?
Nitrogen reacts with oxygen forming Nox gases (nitrogen monoxide) (nitrogen dioxide) NO, NO2
c. What condition is necessary for the formation of these gases?
Very High temperatures
d. In what common object is this condition found?
Cars
e. Why is this condition needed for nitrogen to react?
To break the strong triple covalent bonds because nitrogen is a diatomic molecule (Inert) and the triple bond is strong therefore requires high energy (temperature)
f. What are the dangers of the products from this reaction?'
Asthma, Lung diseases, Death, Life expectancy decreases by 9 years