To go from molecules, we first need to convert to moles and then convert to grams.
To convert from molecules to moles, we need to divide by Avogadro's constant.
1.15*10^21 molecules * (1 mole/6.022*10^23 molecules) = 0.0019097 moles
To convert from moles to grams, we need to use the molar mass.
The molar mass of P₂O₅ is (2*30.98)+(5*16.00) = 141.96
You can find the molar mass using the periodic table.
0.0019097 moles * (141.96 grams/1 mole) = 0.2711 grams.
Since we have 3 significant digits in 1.15*10^21, that means our final answer is limited to 3 significant digits.
Your final answer is 0.271 grams.
