Final answer:
To find the grams of oxygen in 85.5g of H2O2, calculate the number of moles based on the molar mass of H2O2 and then use the stoichiometry to find the mass of O2 contained in those moles.
Step-by-step explanation:
To calculate the grams of oxygen in 85.5g of H2O2 (hydrogen peroxide), we start by determining the molar mass of H2O2. The molar mass of H2O2 is 34.0147 g/mol (2*(1.0079 g/mol for H) + 2*(15.999 g/mol for O)).
Then, we calculate how many moles 85.5g of H2O2 corresponds to by dividing 85.5g by the molar mass.
Next, we use the stoichiometry of H2O2, which indicates that there are 2 moles of O for every mole of H2O2. Since the molar mass of oxygen (O) is approximately 16.00 g/mol, we can then calculate the total grams of oxygen by multiplying the moles of H2O2 by 2 and then by the molar mass of oxygen.