Yes. It's a container, it's open, and it contains traces of alcohol. It is a violation of open container laws, and also probable cause for a sobriety test.
Empty and wet, yes. Empty and dry, no.
No more than 1 inch of residue remains
A 1-pint container has 473.176 ml of space in it. (rounded) We have no way of knowing how much alcohol may be in it. For all we know, it may even be empty.
Fill the 5 litre container and empty it into the 9 litre one. Fill the 5 litre (again) and empty 4 litres into the 9 litre container. Now - empty the remaining litre into the 6 litre container. Finally re-fill the 5 litre container and empty into the 6 litre one - and you're done.
In general any pressurized gas container is "empty" when the pressure inside is equal to ambient air pressure. There is still gas in the container, but not enough pressure to expell the gas. Medical oxygen tanks should never be allowed to go below 200psi. The tank is considered empty at this point and should be replaced.
No
An empty gas container actually weighs less than a full container.
Where you can refill and empty container depends on what you want to refill it with. It can be refilled with water from a tap, or with lotion from a refill bag bought from the store.
The empty glass is broken first.
The absolute empty weight of an aircraft, cargo container etc.
It has air inside and other substances which we cannot see with our naked eye. Air is matter so unless the container is a vacuum it will not be empty.
The container volume is missing.