I reckon hard/soft water will definitely come up. Possible questions include,
a) Explain the difference between scale and scum
b) Explain how hard water can be made soft using an ion-exchange column
Also something about the periodic table in the early stages as this has not been common in recent examinations. Example questions are,
c) The periodic table is now based on atomic structure. Explain how
d) Explain in terms of electrons why fluorine is the most reactive element in Group 7
Those are for C3. I also think it's pretty safe to say the 6-marker will not be on titrations because that is what came up last year. The flame test always comes up and you will need to know which substances produce which colour.
Any other suggestions?