You should read up on Proust's law, better known as the Law of Definite Proportions. This is a chemical law that defines your question more generally, on why the ratio of elements and ions are always fixed.
Basically, this compound Magnesium(II) Chloride is MgCl2 because it has the same number of protons, neutrons, and electrons all the way. This defines the properties of the compound or atom.
When we are at STP conditions, we can use this conversion: 1 mol= 22.4 L
0.500 mol C₃H₈ (22.4 L/ 1 mol)= 11.2 L
Stomatal pores in plants regulate the amount of water and solutes within them by opening and closing their guard cells using osmotic pressure. In order for plants to produce energy and maintain cellular function, their cells undergo the highly intricate process of photosynthesis .
I am assuming that the apparatus you're referring to would be a container wherein there is water placed inside. To answer your question, I expect the water level to rise when it's placed in warm water and I expect it to fall when placed in cool water. This is because the water molecules get excited when placed in water molecule, thus, moving with more kinetic energy. The opposite goes with cool water.