What mass percent of a solution with 28.5 g of H2O2 and 300.0 mL of water?
To determine the mass percent of a solution, you need to calculate the mass of the solute (in this case, H2O2) and the total mass of the solution.
First, we need to find the mass of H2O2. H2O2 is hydrogen peroxide, and its molar mass is 34.0147 g/mol. To calculate the mass, you can use the formula:
Mass of H2O2 = number of moles × molar mass.
To find the number of moles, divide the given mass of H2O2 by its molar mass:
number of moles = mass of H2O2 / molar mass.
Substituting the values, we get:
number of moles = 28.5 g / 34.0147 g/mol.
Simplifying, we find:
number of moles ≈ 0.838901 mol.
Now, let's calculate the total mass of the solution. This includes the mass of the solute (H2O2) and the mass of the solvent (water). Given that the volume of the water is 300.0 mL, we can assume the density of water is 1.00 g/mL. Therefore, the mass of water is:
Mass of water = volume of water × density.
Substituting the values, we have:
Mass of water = 300.0 mL × 1.00 g/mL = 300.0 g.
The total mass of the solution is then the sum of the mass of H2O2 and the mass of water:
Total mass of solution = mass of H2O2 + mass of water.
Substituting the values, we get:
Total mass of solution = 28.5 g + 300.0 g = 328.5 g.
Finally, we can calculate the mass percent by using the formula:
mass percent = (mass of H2O2 / total mass of solution) × 100.
Substituting the values, we have:
mass percent = (28.5 g / 328.5 g) × 100 ≈ 8.68%.
Therefore, the mass percent of the solution with 28.5 g of H2O2 and 300.0 mL of water is approximately 8.68%.