Does an iPhone charger use electricity when still plugged?

1. Does it still use electricity even if the phone is fully charged, but still plugged?
2. Does it still use electricity when there are no iPhones connected but it is still plugged?

I'm a little curious because it is hot when I charge, but when it is fully charged with my phone still charging, there's a little warmth.

If the answer is yes, (this might sound funny to you guys) but where does the electricity go? Wouldn't it just loop around the socket?

Yes it does (very little), and a lot of what doesn't get used ends up as heat.