Take a look at that breaking chain. Take a look at the distance between Iron Man's hands. Put the chain back together in your mind's eye. Why is it breaking? The chain is actually longer than the distance between IM's hands.

This is something to always keep in mind, if you want to draw a shot like this. The unbroken chain should be shorter than distance between whatever two points (hands in this case) are moving apart and causing it to break. If you want the "dramatic moment" you can pick the precise instant the chain breaks, so it's still stretched tight (as we often see in shots of Superman breaking chains across his chest), but there still needs to be a clear indication that the chain has been pulled out longer than its unbroken length.