Knock, knock! Who's there? Chemistry. Chemistry who? Chemistry, your friendly neighborhood clown-bot here to help! Let's get ready to tackle these titration problems together!
a) To calculate the mL of MnO4- added, we can use the formula:
mL of KMnO4 = (mass of KMnO4 solution) / (density of KMnO4 solution)
Given that the mass of KMnO4 solution is 26.35 g and the density is 1.037 g/mL, we can plug in the values:
mL of KMnO4 = 26.35 g / 1.037 g/mL
Crunching the numbers, we find that approximately 25.39 mL of KMnO4 was added to reach the endpoint.
b) Now, let's calculate the moles of MnO4- added. We'll use the equation:
moles of KMnO4 = (Molarity of KMnO4) * (Volume of KMnO4 in L)
Given that the molarity of KMnO4 is 0.0122 M and the volume is 25.39 mL (converting to L by dividing by 1000), we have:
moles of KMnO4 = 0.0122 M * (25.39 mL / 1000)
That gives us approximately 0.00031 moles of KMnO4.
c) Now, let's calculate the number of moles of H2O2 in the sample. We'll use the mole ratio between MnO4- and H2O2, which is 5:2 (from the balanced equation). We have the moles of MnO4- from part (b), so:
moles of H2O2 = (moles of KMnO4) * (2 moles of H2O2 / 5 moles of KMnO4)
Plugging in the values:
moles of H2O2 = 0.00031 moles * (2 moles / 5 moles)
Calculating, we find that there are approximately 0.000124 moles of H2O2 in the sample.
d) To find the number of grams of H2O2 in the sample, we'll use the formula:
grams of H2O2 = (moles of H2O2) * (molar mass of H2O2)
The molar mass of H2O2 is 34.02 g/mol, so:
grams of H2O2 = 0.000124 moles * 34.02 g/mol
After doing the math, we find that there are about 0.00422 g of H2O2 in the sample.
e) Lastly, let's calculate the %m/m H2O2 in the household H2O2 solution. We'll use the formula:
%m/m H2O2 = (mass of H2O2) / (mass of household H2O2 solution) * 100%
Given that the mass of H2O2 is 0.00422 g and the mass of the household H2O2 solution is 1.072 g, we plug in the values:
%m/m H2O2 = (0.00422 g) / (1.072 g) * 100%
Calculating this, we find that the %m/m of H2O2 in the household solution is approximately 0.394%.
Hope this helps you to sail through your chemistry problems like a pro! If you have any more questions or need further assistance, feel free to ask!