0.45 grams of P₂O₅
To find the total molecules, we first need to find the moles of P₂O₅ and then use Avogardo's constant to find the number of molecules.
To convert to moles, we first need to use the molar mass.
The molar mass of P₂O₅ is (230.98)+(516.00) = 141.96
You can find the molar mass using the periodic table.
0.45 grams (1 mole/141.96 grams) = 0.0031699 moles
Now we multiply by Avogadro's constant to convert to moles.
0.0031699 moles (6.02210^23 atoms/1 mole) = 1.910^21 molecules
Since 0.45 has 2 significant figures, our final answer is also limited to 2 significant digits.
Your final answer is 1.9*10^21 molecules.