This problem is very easy to answer. You simply have to look at the subscripts of each element of the compound.
1. For caffeine, which has a molecular formula of C₈H₁₀N₄O₂, it contains 8 atoms of Carbon, 10 atoms of Hydrogen, 4 atoms of Nitrogen and 2 atoms of Oxygen.
2. For Iron(III) Sulfate, which has a molecular formula of Fe₂(SO₄)₃, it contains 2 atoms of Iron, 3 atoms of Sulfur, and 12 atoms of Oxygen.
Moles = mass / molar mass
molar mass of O2 is 32
therefore moles = 72/32
= 2.25 moles
The answer would be volume
A. because the wax was hot meaning it’s molecules are moving fast and then cooling down which slows down the molecules. this is the same thing that happens when water changes it’s state to ice