AQA GCSE Chemistry - C2 & C3 (14th May 2015)

omg!!! thank you so much

Can anyone help me out with electroplating? I know the basics but not enough for a 6 mark question on it :/

1. You will be given 2 (possibly 3) elements
e.g Sodium (Na) and Sulphur (S) and Oxygen (O)

2. You will be given the mass or the percentage - they both work the same way
e.g 4.6g of Na and 3.2g of S and 6.4g of O

3. You need to get the Mr of each element by looking at the top number on the periodic table.
In this case Na is 23 and S is 33 and O is 16

4. Divide the percentage or mass of each by its own Mr value
4.6/23 = 0.2 and 3.2/33 = 0.1 and 6.4/16 = 0.4

5. Divide this result by the lowest result just obtained.
So the lowest result was 0.1 - So all 3 are divided by 0.1
0.2/0.1 = 2 and 0.1/0.1 = 1 and 0.4/0.1 = 4

6. Put these 3 values in front of the symbols
Na2 S1 O4
= Na2SO4
This is the final answer

Can you help me plzz!! How did you get 4.6 (Na) 3.2 (S) and 6.4 (O)???????

I'm stuck

Hi here's a 5 mark question I did on electroplating earlier if that might help you?

Explain how and why a copper cup would be electroplated with silver.
The cup would act as the negative electrode, and the positive electrode should be a block of pure silver metal. The electrolyte used needs to be an ionic substance containing ions of the plating metal (silver). For example, silver nitrate solution could be used. It is important that the electrolyte is in solution so that the ions can move to carry charge. The silver ions in the electrolyte will move to the negative electrode (the cup) because they are positively charged. Here each silver ion will gain 3 electrons and be reduced to silver atoms, hence the cup will be plated with silver metal. The silver metal at the positive electrode is required to top up the solution with silver ions. Electroplating is done to coat the surface of one metal with another. In this case, it is done for decoration, to make the cup look nice, because making a pure silver cup would be too expensive.

In step two they said it's an example.

this sounds pretty immature but the way I remember flame test colours is "little cock sods yell penis loudly caressing rainbow balls gently"
(Lithium crimson, sodium yellow, potassium lilac, calcium red, barium green)

Have titration calculations come up in the past? I think they're in the book but i haven't really seen them in past papers and i want to know how likely it is that they will come up.

Does anyone know the reason for electroplating?

Or, alternatively:
PoP CaR BaG LiC SoY
Potassium - Purple,
Calcium - Red,
Barium - Green,
Lithium - Crimson,
Sodium - Yellow

pop car bag lic soy - doesn't make a full sentence, but might be less weird if someone hears you muttering it to yourself XD

I think there was one last year

Haha it's okay! Good luck tomorrow and let me know if there's anything else!

We haven't even covered it in class!! But I know it's to make things look pretty (like copper items electroplated in silver so they look better etc)

Ohhh, thanks I found it!

can anyone help answer this, what properties make ethanol a useful solvent?