(Original post by MissGeek)
Here is an unofficial mark scheme of all the questions and answers I can remember. I do apologise in advance if the questions are not worded in the correct order, or if the order confuses you.
Why are chloride ions attracted to the positive electrode? (1)
Opposite charges attract/chloride ions have a negative charge
I can't remember, I think it was something on ions, or alkalis? (1)
Why is hydrogen formed? (1)
Hydrogen is less reactive than sodium
Draw the diagram (Hydrogen and Chlorine) (I THINK) (1)
Both must have a full outer shell.
What type of bonding is it? (1)
What type of ions make the solution pH 1? (1)
What type of ions make the solution alkali? (1)
Calculate the number of ? in 1 mol^3 of ? (gas canister question) (1)
I did 53.? - 51.? (I don't know if this is right though)
Calculate the mean mass of gas results. (2)
Miss out anomaly to get answer, however, if you showed your workings, you could still get 1 mark.
Suggest 2 causes of this experimental error (2)
I put weighing error in measuring gas canister, human error, recording error, may have been a systematic error (unsure, please correct me if I'm wrong)
Why should they repeat the test more (1)
Make it more reliable
Allows them to spot any anomalies
Allows them to calculate a mean/average
What type of acid makes the magnesium hyrdoxide react to form calcium chloride? (1)
Explain how the magnesium hydroxide (I think) can be separated from the calcium chloride. (1)
I can't remember what I put.
Suggest how the calcium chloride can be made into a solid? (1)
What is oxidation? (1)
Electrons are lost.
Explain why the best yield is produced when the pressure is higher (1)
There are more (gaseous) reactant molecules than (gaseous) product molecules.
Explain why, in terms of particles, the rate of reaction increases when temperature increases. (2)
The particles gain energy, they move faster and collide more frequently.
Explain why the pressure is not higher than 200 atmospheres in the Haber process (1)
It would be more expensive.
Explain why a temperature of 450 is suitable (can't remember exactly how it was worded) (1)
The forward reaction is exothermic
Explain why it doesn't matter if a low yield of ammonia is produced in the Haber process (2)
The unreacted hydrogen and nitrogen are reacycled and can be used and reacted again to form ammonia again.
The reaction is reversible.
Calculate the mass of ammonia that can be made from 2g of nitrogen (3)
2.4g (1 d.p.)
In Haber Process, a maximum of 80kg can be produced. 12 kg is produced. Calculate the percentage yield. (2)
Diamond is hard. Explain why it is hard, refer to structure and properties in your answer (3)
Each carbon atom is covalently bonded to 4 other carbon atoms. The bonds are strong and a lot of energy is required to break the bonds. There are no delocalised electrons in diamond due to each carbon atom being covalently bonded to 4 other carbon atoms.
Calculate the relative formula mass of C3H8. C=12, H=8 (2)
Explain the structure of gold. (3)
There is metallic bonding in gold. There are fixed positive ions and delocalised electrons which are free to move around. There are electrostatic forces of attraction between the electrons and positive ions.
Explain why gold is a good conductor of electricity (1)
It has delocalised electrons