Your question is incomplete. However, I found a similar problem fromanother website as shown in the attached picture.
To solve this problem, you must know that at STP, the volume for any gas is 22.4 L/mol. So,
Moles O₂: 156.8 mL * 1 L/1000 mL* 1 mol/22.4 L = 0.007 moles
Mass calcium: 0.007 mol O₂ * 2 mol Ca/1 mol O₂ * 40 g/mol Ca =
<em> 0.56 g Ca</em>
The postulate of Dalton's atomic theory that atom is indivisible particle and can be subdivided into smaller particles was later changed because atom can be divided into neutrons, protons and electrons. It was changed because after later finding out that the atom can be divided, the theory was changed to the correct finalized theory.
Hope this helps!!!