Long answer·Standard multi-step (3/5)·No calculator
Difficulty guide
The label describes the problem, not your ability.
1/5 - Foundational
Warm-up setup; checks one basic idea.
2/5 - Routine exam skill
Normal syllabus skill; usually one main rule or interpretation.
3/5 - Standard multi-step
Exam-style problem with multiple steps or a common trap.
4/5 - Hard exam skill
High-end exam problem; combines methods carefully.
5/5 - Challenge
Stretch problem beyond normal exam pressure.
Question
Plan a practical to compare the foaming capacity of soap in distilled water and hard water.
Total: 7 marks
(a) List the materials and controlled conditions. (2 marks)
(b) Describe the procedure. (3 marks)
(c) State the expected observation and inference. (2 marks)
Something wrong with this item?