Use Roy Tasker’s video model VisChem, or Kahn Academy, and post on Blackboard. There are a lot of online formative practise quiz questions, for example, in Kahn Academy.
Use Lego pieces. For example, HCl built out of Lego. Use a little blue brick and a yellow one, showing physically that on this side you’ve got one blue Lego brick and then on this side you’ve got two and so on, trying to make them see them not as chemical formulas but identities of some sort.
Try demonstrating the reaction first, to show the macroscopic changes that occur, before introducing the equation. Copper in silver nitrate solution is a standard one. Explain it in terms of particles, the ions, atoms, show a video representation (for example from YouTube) of these changes, and then explain the whole thing in terms of the symbolic chemical equation to represent the overall change.
You can use analogies to everyday objects and there are a variety of things you can use in that way, such as pebbles and peas to illustrate moles, because they have different masses. Certainly getting them to think about that and then to be comfortable in translating that into a whole lot of different elements you might be comparing.
Something you can do visually in the lecture theatre is to take in some things you wish to connect and make up an item. Or in PhET, for example, there’s a little activity you can do making sandwiches and you can work out how much you need of which one and whether you’ve got something that’s there in excess or something that’s limiting. It's based on the molar ratios or the stoichiometric coefficients, which in turn are based on the number of moles reacting.
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
Using clickers, put up say four ideas, and say, who thinks A and who thinks B, C, D. Now in the groups they need to defend their answer, and to talk about it. That way you get the feedback but you don’t have to say Bill, Mary, Jim, Jack, what do you think? You can get them to click their answers.
