The marks aren't fixed . Sometimes it's eight , sometimes ten , sometimes twelve . You don't need hypothesis or variables or anything like that , planning of experiment is the one in paper three .
In paper two , you'll need to describe an experiment using passive voice .
You need :
1 . Apparatus and Materials ( sometimes they want chemicals only but I always give apparatus just to be safe ) .
2 . Procedure ( this carries most marks , sometimes up to eight marks (
3 . Observation / Chemical equation / Table / Graph ( depending on the question , normally Salts questions require chemical equations , and electrolysis experiments require observations at the anode or cathode ) .
That's all . If you can fulfil these criteria , you don't need to worry about the marks .
SPM Chemistry past year book has HORRIBLE answers . Look at trial paper mark schemes instead .