Household hydrogen peroxide is an aqueous solution containing 3.0% hydrogen peroxide by mass. What is the molarity of this solution? (Assume a density of 1.01g/ml .)
A 3.0% by mass solution of H2O2 contains 3.0 g of H2O2 per 100 g of solution.
(3.0 g H2O2 / 100 g solution) x (1.01 g solution / 1 mL solution) x (1000 mL / L) = 30.3 g H2O2 / L
(30.3 g H2O2 / L) x (1 mole H2O2 / 34.01 g H2O2) = 0.8909 moles H2O2 / L = 0.89 M to 2 sig figs
Household hydrogen peroxide is an aqueous solution containing 3.0% hydrogen peroxide by mass
To find the molarity of the solution, we need to determine the number of moles of hydrogen peroxide in one liter of the solution.
Step 1: Calculate the mass of hydrogen peroxide in one liter of the solution.
Since the solution contains 3.0% hydrogen peroxide by mass, this means that there are 3.0g of hydrogen peroxide in 100g of the solution.
Assuming the density of the solution is 1.01g/ml, this means that one liter of the solution has a mass of 1010g (1000 ml x 1.01 g/ml).
Therefore, the mass of hydrogen peroxide in one liter of the solution is (3.0g/100g) x 1010g = 30.3g.
Step 2: Convert the mass of hydrogen peroxide to moles.
The molar mass of hydrogen peroxide (H2O2) is 34.02 g/mol.
To convert the mass of hydrogen peroxide to moles, divide the mass by the molar mass:
30.3g / 34.02 g/mol = 0.892 mol.
Step 3: Calculate the molarity.
Molarity is defined as moles of solute divided by liters of solution.
Since we have 0.892 moles of hydrogen peroxide in one liter of solution, the molarity is:
Molarity = 0.892 mol/ 1 L = 0.892 M.
Therefore, the molarity of the household hydrogen peroxide solution is 0.892 M.
To determine the molarity of the solution, we need to first calculate the number of moles of hydrogen peroxide present in 1 liter (L) of the solution.
Given:
- Percentage of hydrogen peroxide by mass = 3.0%
- Density of the solution = 1.01 g/mL
To calculate the molarity, follow these steps:
1. Convert the percentage to grams:
Since the solution contains 3.0% hydrogen peroxide by mass, for every 100 g of the solution, there are 3.0 g of hydrogen peroxide.
Therefore, we can assume that 1 L (1000 mL) of the solution contains 30 g of hydrogen peroxide.
2. Convert grams to moles:
To convert grams to moles, we need the molar mass of hydrogen peroxide (H2O2). The molar mass can be calculated by adding the atomic masses of each element in the compound.
The molar mass of H2O2 = 2(1.01 g/mol) + 2(16.00 g/mol) = 34.02 g/mol
Now, we can calculate the number of moles of hydrogen peroxide as follows:
Moles = mass / molar mass
= 30 g / 34.02 g/mol
≈ 0.8812 mol
3. Calculate the molarity:
The molarity is defined as moles of solute per liter of solution.
Therefore, the molarity of the hydrogen peroxide solution is:
Molarity = moles / volume
= 0.8812 mol / 1 L
= 0.8812 M
So, the molarity of the household hydrogen peroxide solution is approximately 0.8812 M.