I'm sorry to see that you missed qualification. Please don't worry about it overly; these things happen, especially when we are getting used to the markscheme.

The following are some notes that I hope will help. Please also check through the scripts to see the definitive marks and the comments, which really help to clarify the intentions of the MS for some questions:

1a
Lines of best fit are needed for M1. Curves or other lines are not worth the mark. Also the volume must be given to 1dp for M2(last line of the MS)

ECF can earn many marks. For example in 1b ii, if the volume is incorrect for M1, the error carries forward and 2 marks can be earned if the moles are correct and the final calculation is done correctly.

Apply owtte. Many candidates are not native speakers and may use slightly unusual words or phrases, eg. 2b "fired" is an alternative to "bombarded" in the electron gun of a mass spectrometer. (but this doesn't apply to precise chemical terms, such as compund names!)

Check state symbols carefully in 3a

4a Homologous series do not have same empirical formula. Its only the general formula which is the same.

Watch out for bogus species in the free radical mechanism of 4b. Its easy to get fooled by a dot. I have seen many strange species in the propagtion steps already!

5c answer like "to replace the ammonia" are insufficient for M2

5e ii "uneconomical" must be supported by a reason

6a iv The imf of both species need to be given

6b the necessity of "attraction" is something highlighted in the notes circulated just after marking began. If these bond descriptions neglect to mention attraction, they don't get M1

Overall, just take your time early on until you get used to the MS.

Please acknowledge this message and ask if there is anything you want to clarify. I will then be able to release more scripts for you.