Q: if working out for an hour, how much calories will be burned?

A: Sorry, there's no way of answering that exactly. An hour of intense cardio or intense weight lifting can burn 500 calories or more. But the main calorie-burning benefits of weightlifting (which cardio does not provide almost at all) is the calorie-burning AFTER the workout as your muscles repair the damage done by lifting heavy weights. Those calories will vary a lot, depending on muscles worked, intensity, diet, age, etc. but on the whole can easily exceed the calories actually burnt in the gym.