It is exactly what it says. The number of valves the engine has per cylinder. If you have 16 valves on an 8 cylinder engine, you have 2 valves per cylinder.
Camshaft opens and closes the valves The CAMSHAFT is connected to the CRANKSHAFT with gears so that the valves (intake and exhaust valves) are opened and closed at the proper time for each cylinder, and fully sychronized for with the movement of all of the other parts of the engine.
Valves per cylinder makes one's engine more powerful or less powerful. A engine that has 2 valves per cylinder is better that a engine that has only one.
yes during ventricular systole AV valves are closed.
16 valves
When #1 piston is at its upper most position in the cylinder bore and both intake and exhaust valves are closed
The piston is on the up stroke to compress so both valves are closed
Top Dead Center, unless otherwise specified, refers to when the piston in cylinder number one reaches the closest it can be to the cylinder head. All the valves should be closed at this point.
3 valves per cylinder ( according to the owners manual )
With springs.
The best way to tell if the valves are closed is to observe the rocker arms. When they are both at the top of their travel, valves are closed. Feel the rocker arms and try to move them, if they move their at the top of their travel.
To adjust the valves on a Chevy Celebrity 2.5L 4 cylinder engine I would recommend that you consult a manual, either factory or Chilton or Haynes. There you will find not only how to do the adjustment but the settings to use to adjust the valves in the correct closed position.