Grade 12 Chemistry is one of the most challenging courses in Ontario high schools, and it's the same with Physics. As with typical chemistry problems, many of the questions are based on possible outcomes since Chemistry deals with so many diverse elements (e.g., what is the product of reacting chemical X with Y).
Many students are not familiar with this type of problem-solving strategy, so they prefer step-based or formulaic-based problems. But science students cannot escape this in the university, so they'll have to learn the skills.
The complexity of the concepts in Grade 12 Chemistry is high and may sometimes be frustrating. They include enthalpy, orbitals, equilibrium, and organic nomenclature, which most chemistry students usually find tasking.