NCEA L2 Chemistry 91166 Exam Prep 2026: Rates, Equilibrium, Kc, Strong & Weak Acids, pH

One complete exam lesson for NCEA Level 2 Chemistry AS 91166 (Demonstrate understanding of chemical reactivity), external exam Nov 2026. In this lesson: Rates and collision theory, The four factors, Practical: concentration and rate, Dynamic equilibrium, The equilibrium constant, Kc, Changing the conditions, Acids and bases: proton transfer, Strong and weak acids and bases, pH, [H₃O⁺] and Kw. Then practice questions, a full model answer and a summary. One full lesson, about 61 minutes, with every step worked on screen so you can pause and try first. Exam: NCEA Level 2 Chemistry AS 91166 (Demonstrate understanding of chemical reactivity), external exam Nov 2026; also useful for A-Level, IB, AP and VCE Chemistry. What's covered (chapters): 0:00 What this paper asks of you 4:58 Rates and collision theory 8:03 The four factors 13:47 Practical: concentration and rate 17:57 Dynamic equilibrium 20:29 The equilibrium constant, Kc 25:30 Changing the conditions 30:21 Acids and bases: proton transfer 34:01 Strong and weak acids and bases 38:42 pH, [H₃O⁺] and Kw 44:50 Where marks are lost 48:45 Practice set A 50:51 Practice set B 54:45 Full model answer 59:34 Summary and close Who it's for: Students sitting this paper in 2026 who want one structured revision lesson with worked practice, plus teachers and tutors looking for a full-topic recap. How to use it: pause before each worked answer, try it yourself, then check. Eurekha is not affiliated with, and this video is not endorsed by, any exam board, ministry or education authority named here. All questions are original. Always check the official documents and timetable for your own exam. ▶ Watch next: NCEA L2 Chemistry 91165 Exam Prep 2026: Naming, Isomers, Organic Reactions & Polymers    • NCEA L2 Chemistry 91165 Exam Prep 2026: Na...   🔔 Subscribe to Eurekha for free full-length exam lessons:    / @eurekha-c1g   If this helped, like the video and share it with a classmate. About Eurekha: free, exam-focused lessons in maths, science, English and computing, made in Melbourne, Australia for students following any curriculum worldwide. #NCEA #NCEA2026 #ExamPrep