To find the number of H3PO4 molecules in 125 grams, calculate the molar mass, use it to determine the moles, and then multiply by Avogadro's number.
To calculate the number of molecules of H3PO4 in 125 grams, you first need to determine the molar mass of H3PO4. The molar mass can be calculated by adding the atomic masses of all atoms in the compound: 3 hydrogen atoms, 1 phosphorus atom, and 4 oxygen atoms. After finding the molar mass, divide the total mass of H3PO4 by its molar mass to find the number of moles. Finally, to find the number of molecules, you can multiply the number of moles by Avogadro's number (6.022×10²23 molecules/mole).
Example: The molar mass of H3PO4 is approximately 98 grams/mole (1×31+3×1+4×16). For 125 grams of H3PO4, the calculation will be:
- Number of moles in 125 g of H3PO4 = 125 g ÷ 98 g/mole.
- Number of molecules = Number of moles × 6.022×10²23 molecules/mole.
Using this method, you'll obtain the total number of H3PO4 molecules in 125 g.