Calculating Hydrogen Peroxide Mass Percent in Redox Titration

• ylperon
In summary, the question asked how many molecules of hydrogen peroxide were in the whole bottle, and the solution was to use the mass percent of hydrogen peroxide in the solution. The calculated average mass percentage was 2.5% H2O2.
ylperon

Homework Statement

How many molecules of hydrogen peroxide were in the whole bottle?
(See Data)

Homework Equations

Data.
Balanced equation.
6H+ + 2Mno4- + 5 h2o2 --> 2Mn2+ + 5O2 + 8 H2O
I used 26.85 mL of MnO4- the first trial, and 29.80 mL in the second trial.
10.000 g of H2O2 used in the solution being titrated.
3.951 g of KMnO4 solid used to make the standard solution.
The molarity of the KMnO4 solution is .1000 M

The Attempt at a Solution

I first tried to find the mass percent of hydrogen peroxide I used in the solution.
26.85 mL MnO4 - conversion to liters ---> .0269
X / .0269 L = .1000 M
X= .00269 mol MnO4-
Convert to grams hydrogen peroxide.
.00269 * (5/2 molar ratio) * 34.02 molar mass of H2O2 = .23 g H2O2
.23 / 10.000 g h2o2 used = .023
.023 * 100 = 2.3% by mass H2O2

I did the same for the second trial with 29.80, and ended up with 2.6% mass H2O2.
The average of the mass percents was around 2.5 % H2O2

Where do I go from here? Did I calculate the mass percentage of hydrogen peroxide correctly?

ylperon said:
10.000 g of H2O2 used in the solution being titrated.

Please elaborate. There was either 10 g of hydrogen peroxide, or 0.23 g of hydrogen peroxide.

Do you mean 10 g of SOLUTION of hydrogen peroxide?

--

Borek said:
Please elaborate. There was either 10 g of hydrogen peroxide, or 0.23 g of hydrogen peroxide.

Do you mean 10 g of SOLUTION of hydrogen peroxide?

--

I meant we used 10 g of hydrogen peroxide as the analyte.
The .023 g was calculated using stoichiometry from the mol of MnO4-.

1. What is a redox titration?

A redox titration is a type of chemical analysis that involves measuring the change in oxidation state of a reactant in a chemical reaction. It is used to determine the concentration of an unknown substance by carefully adding a known reactant until the reaction is complete.

2. How does a redox titration work?

A redox titration works by using a redox indicator, which changes color when the reaction is complete, to signal the endpoint of the reaction. The volume of the known reactant needed to reach the endpoint is then used to calculate the concentration of the unknown substance.

3. What is a redox indicator?

A redox indicator is a substance that changes color when the oxidation state of a solution changes. It is used in redox titrations to indicate when the reaction is complete and the endpoint has been reached.

4. What are some common examples of redox titrations?

Some common examples of redox titrations include the determination of iron in iron supplements, the analysis of copper in brass, and the quantification of vitamin C in fruit juices.

5. What are the limitations of redox titrations?

Redox titrations can be limited by the accuracy of the redox indicator used, as well as the potential for side reactions to occur. Additionally, redox titrations may not be suitable for substances that are unstable in the presence of oxygen or other reactants.

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