Oh, you went from an over-simplified model to an over-over-simplified model to do your calculations. Well done. you are aware that the (symbol) model is inaccurate due to not properly accounting for gravitational forces, don't you?
We didn't need to account for gravitational forces, it's high school water chemistry. This is why it burns, this is how you find out how well it burns, these are the chemicals emitted when it burns, lets move on to something else. Simple, and just as simple to teach with a realistic model of atoms instead of a fictious model.