The way back-titrations are taught is often confusing. Get them to concept map the calculation. So, instead of trying to do the calculation in their head, map it out starting from where they end up, and then relate each of those steps to where that number is coming from. Have them think about it like it’s a reaction. Because they know how to do the math, and they can understand how to do it for a reaction. An example is the dissolution of calcium carbonate and trying to get them to work out how much carbonate is in a limestone sample.
Try and get across the bigger picture - everything you're going to do is going to be a model. Nothing is going to be right. Nothing is going to be wrong. Nothing is going to be exactly the way it is. Everything is a series of models.
Try to show students that the fundamental form of matter is energy. Then that this can be represented as particles with mass or as waves (wave functions). Link to YouTube Video: Particles and Waves
Students come in, like all of us, trying to apply macroscopic analogies to everything – (the billiard balls colliding and similar things) and using them as models for atoms. Try to get across that it's a simple analogy but it's not as simple as that in reality. I guess go back a step and try and show that everything is really just a form of energy.
It’s very difficult to get students to ask questions because they feel they’re being picked on. But if they start putting up their hand and other students see that you’re prepared to be receptive to that then more and more will start putting up their hands. Invariably they’re good questions which still cover the topic. So you should have enough content for your lectures but not so much that you’ve got to force it to finish. The question that they ask, which they’re worried is a dumb question, is actually the question that probably nearly everyone else wants to ask but is afraid to ask.
Use small group student-centred interaction using structured work sheets that logically develop students' conceptual understanding. It’s a learning cycle approach.