Guest Posted February 3, 2016 Report Share Posted February 3, 2016 Hei. I need desperate help with this Redox Titration lab calculations. I suck at chemistry, I go for extra help and read text book and only understand for one day, and then I'm confused the next. Anyways, we had to experimentally determine the % H2O2 by mass in a solution given: MnO4 + H2O2 + H -> Mn + O2 + H2O (charges are given). Procedure: Combine (in order) 25 drops of H2O2 solution, 20.0 mL of deionozed water, and 20.0mL of 1.00 M +/- 0.05 M H2SO4 in an Erlenmeyer flask. Titrate with 0.0400 +/- 0.0005 M KMnO4 until solution decolorizes to a persistent pink. Raw Data: Mass of Erlenmeyer flask: 115.711 gDrops of H2O2 solution: 25Mass of Erlenmeyer flask and H2O2 (+/- 0.002) g: 117.003gVolume of water added (+/- 0.2) mL: 20.00Molarity of H2SO4 added (+/- 0.05) M: 1.00Volume of H2SO4 added (+/- 0.2)mL: 20.00Initial volume of KMnO4 added (+/- 0.2)mL: 50.00Final volume of KMnO4 added (+/- 0.2)mL: 23.69Molarity of KmnO4 added (+/- 0.005) M: 0.0400 Processed data: Mass of H2O2 solution used (+/- 0.004)g:Relative Uncertainty (+/- %)g:Total Volume of KMnO4 used (+/- 0.04) mL:Relative Uncertainty (+/- %) mL: Do I have to use the half reactions to balance the equation? How do I calculate the % mass H2O2 if I'm only given 25 DROPS? Please, I need help. I was going to do (Molarity H2SO4)(VOLUME H2SO4) = (MOLS H2SO4), then use stoichiometry, but I wasn't sure. I'm I in the right path? Reply Link to post Share on other sites More sharing options...
kw0573 Posted February 4, 2016 Report Share Posted February 4, 2016 1) Yes balance the reaction2) It looks like potassium permanganate is your limiting reagent (can you figure out why?) and all species are in stoichiometric ratios as presented in the balanced reaction3) If you did the drops correctly, typically you would know the volume for each drop (eg 1 mL/drop or something). 4) Use stoichiometry to find moles of hydrogen peroxide. Then there you should be able to convert to mass ratio 1 Reply Link to post Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.