Advanced Higher Chemistry 2018-19

Can somone help me with this question? I thought it was A but its actually B.

n=cv
n=2 x 0.05L
n=0.1 mol

to find the diluted concentration you have to add the volumes together
c=n/v
c=0.1mol / (0.05+0.2)
c= 0.4 mol l-1

Hi guys wondering if someone could help me regarding the project:

So for my project I’ve done, investigations the mass of oxalis acid in spinach leave through the use of volumetric analysis. And for my method I kind of made it up with the information I researched online and discussing with my chemistry teacher. And apparently we need to have a reference for the method but I’ve just put acknowledgements in, is that enough or will I be penalised?

You don't need to reference an exact method, but you should be referencing all the sources you used for the project.
Acknowledgements don't gain or lose you any marks, but it's still good to include.

There isn't a mark awarded specifically for references in the methods section.

Okay thank you! I’ve referenced all other sources used and hopefully that all be sufficient.

Sounds like that will be fine

Cheers
Also another quick question, do we reference images and diagrams as well?

Cheers
Also another quick question, do we reference images and diagrams as well?

Can someone explain this question please?

Can someone help with these questions please

The answers say A, B and C but I’m not sure if the answers are right

For the first one about the aqueous solutions, you're expected to know that Zinc is always colourless in solution. I'm sure this is due to electronic configuration, but I'd look at up just for clarification. Hence why the answer is A.

For the second question, the question is asking what reagent will form a silver mirror with Tollens reagent - which is just another way of asking you to identify the aldehyde (-CHO group). Therefore, the answer is B (ethanal).

For the last question, you are being asked to work out the 'co-ordination number' of the transition metal. This is basically just how many bonds the metal makes. To find this out, just count the number of other molecules which the transition metal bonds with. (Now I'm confused because I would have said D but... I guess it's C lol

hi can anyone help me with this question please?

2. Phosphorus forms different compounds with chlorine.

(a) When heated, phosphorus pentachloride dissociates to form phosphorus
trichloride and chlorine.

PCl5(g) -> PCl3(g) + Cl2(g) ΔH = +124 kJ mol−1

In an experiment to determine the equilibrium constant, K, 0∙100 mol of PCl5 was placed in a sealed 1∙00 litre flask and heated to 250°C. At equilibrium 0∙0420 mol of PCl3 had been formed.
(i) Calculate the equilibrium constant, K, for the reaction at 250 °C

Can someone help with q 6,

I could be mistaken but I would say A-pH as dilution/adding water changes the concentration of H+ ions there are per litre of solution. In other words pH is ‘concentration dependent’. The rest will remain unaffected as:
-there are the same number of H+ ions after dilution
-Pka And ka aren’t affected by concentrations and are constant values for a molecule

I think the square brackets around the H+ means concentration so as you said the H+ concentration would change and the answer would be B.