Final answer:
The average molarity of a commercial 3% hydrogen peroxide solution, assuming the density is similar to that of water, is approximately 0.882 M. This is determined by converting the mass percentage to moles of hydrogen peroxide per liter of solution.
Step-by-step explanation:
The average molarity of commercial hydrogen peroxide (H₂O₂) solutions can vary. However, a common concentration for laboratory use is a 3% solution. This percentage refers to the mass of H₂O₂ per mass of the solution. To calculate the molarity of the H₂O₂, you would need to convert this percentage into moles of H₂O₂ per liter of solution.
For example, if we assume that the density of a 3% H₂O₂ solution is close to that of water (1 g/mL), 100 g of this solution would contain 3 g of H₂O₂. Given that the molar mass of H₂O₂ is approximately 34.0147 g/mol, you would have 0.0882 moles of H₂O₂ in 100 mL of solution, or 0.882 M when converted to moles per liter.
Note that this is a simplified calculation and the real molarity could be slightly different based on the actual density of the solution and its exact concentration.