Answer:
About 0.652
Explanation:
Because the reaction is balanced, we can go straight to the next step. The molar mass of potassium is about 39.098, while the molar mass of hydrogen gas is 2 and the molar mass of water is 18. Therefore, 25.5g of potassium would be about 0.652 moles, and 220 grams of water would be about 12.222 moles, making potassium the limiting reactant. Since there is a single unit of each compound on both sides of the equation, there would be an equal amount of moles of potassium and hydrogen, and therefore about 0.652 moles of hydrogen gas would be produced. Hope this helps!
You could say that hydrogen and Oxygen molecules are similar in that their chemical formula is H2 and O2. That means there are 2 "atoms" per molecule. I don't know how to put water into this because water molecules are quite different from H2 and O2. Even the intramolecular forces are quite different.
H2 and O2 are different in their masses per molecule.One is quite a bit heavier than the other. They can be quite explosive if they are put in the same container. I once heard a NASA engineer say that Hydrogen is a "real snake" to handle. It is used for rocket fuel. Both are compressed a great deal.
You need to know the neutrons because the atomic mass is made up of the number of protons and neutrons