Moles in the container : 0.306
Further explanation
Given
30 g of H3PO4
Required
moles in container
Solution
A mole is a unit of many particles (atoms, molecules, ions) where 1 mole is the number of particles contained in a substance that is the same amount as many atoms in 12 gr C-12
1 mole = 6.02.10²³ particles
While the number of moles can also be obtained by dividing the mass (in grams) with the molar mass of element or molecule
MW of H3PO4 = 3.1 + 31 + 4.16 = 98 g/mol
mol = mass : MW
mol = 30 : 98
mol = 0.306