alevel Chem Topics with most marks

What are the key areas I should be focusing In OCR A chem If I'm aiming for a B? The ones that hold the most marks or are easy to master so they're guaranteed marks, I only need a B for my course, so I want to focus effort away from areas that are for more A-A* students.

TDLR: what topics hold the most marks?

Thank you!

Depends on the paper.

Usually, OCR A paper 1, for example is very consistent and you can expect the following:

-A lot on A2 Redox
-A lot on transition elements
-Buffer solutions
-Mole calculations
-A fair bit on enthalpy