The smallest functional and structural unit of an organism, usually microscopic and consisting of cytoplasm and a nucleus in a membrane.
It has many different uses like being used to make the tube of a vacuum cleaner and also can be used to make oil in space crafts.
All you need to do is to look at both sides of the equation and see who has the same element, state, coefficient, and charge and those will be your spectator ions.
In this question, the spectator ions would be 
and 
.
Fills volume of the container.
Why? Because the gas particles have a very weak force of attraction so they move very freely and so they always fill the volume of containers.
Yes, just like dissolving salt in water and evaporating it. You would be left with the salt crystals.
