Answer:
88g of Sr(NO3)2 are present
Step-by-step explanation:
To solve this question we must, as first, find the moles of oxygen. Based on the chemical formula of strontium nitrate, there are 6 atoms of oxygen per mole of strontium nitrate. Thus, we can find the moles of strontium nitrate and its mass as follows:
Moles Oxygen:
40g * (1mol / 16g) = 2.5 moles Oxygen
Moles Strontium nitrate:
2.5 moles Oxygen * (1mol Sr(NO3)2 / 6mol O) = 0.4167 moles Sr(NO3)2
Mass (Molar mass Sr(NO3)2: 211.63g/mol)
0.4167 moles Sr(NO3)2 * (211.63g / mol) =
88g of Sr(NO3)2 are present