Civil Rights and the 1950s: Crash Course US History #39

Well done and explained! I bought 35% H2O2 about a year ago online and it has decomposed a bit I think, so it might be worth it to find out how much I have left.

How pure is the KMnO4 you have? If the purity is low, then you may have MnO2 present which catalyzes the decomposition of H2O2 and will give misleading results.

Great video

The major sources of error would be the permanganate remaining in the funnel when you weighed the excess KMnO4. Also there seemed to be a lot of it clinging to the side of the jar/beaker during the titration. Better to slow down the rate of flow and wash the sides down with distilled water. Another way to reduce the error would be to use a burette and record the volumes Sorry - yes I do teach chem :)

Or... you could just check the temp of the solution (persumably room temp). Measure the mass of a certain volume of water at the same temperature.. get the density of the h2o2 at that temperature (internet) and calculate it. Much simpler than waste valuble h2so4

@ReactionFactory It wasn't meant as a criticism as such; just pointing out to viewers the sort of thing to look out for if they repeat the experiment. And I agree about the intensity of the colour- try reading a burette through it! It's the only time I let students read from the top of the meniscus!

@Bilbo940 But this wouldn't account for the mass of anything else in the solution. Titration liberates the O2 and thus helps determine the concentration of the H2O2. The acid (others could be used) is required for the MnO4(-) ion to be reduced to Mn(2+) and water ... where is the sub/superscript when I need it :)

im glad i can speed read, yo should make your captions longer for those who cant

@ReactionFactory Depends on the accuracy of you scale, mine can pretty much measure 0,001 quantities so a large volume of peroxide is not needed. Also, in which way can it be contaminated? Pouring it into a clean glass vial is just as much contamination as pouring it into a bottle when first getting it. Here in Sweden Sulfuric acid is illegal to buy in any concentrations. It is still possible to get if you are not making it yourself, but 1 liter can cost up to 45,0 dollars.

H2O2 has a density of 1.463 g/cm3 @25°c H2O has a density of 0.997 g/cm3 @25°c If you are fairly confident that you have no other contaminates could you not simply measure the mass and volume to determine the purity?

Hi, we have a question. We're wondering the concentration of H2SO4 you used to carry this experiment. Thank you in advance. :)

Also, how long did you take to complete the lab?

Concentrated sulphuric acid is an oily liquid, (once known as "oil of vitriol" or just "vitriol").  It is nasty.  It reacts vigorously with water.  Fortunately for you this is not what you have.

Why did you add sulfuric acid? What's the purpose of adding that?

shouldn't the color turns pale pink in titration ????????????

what was the Nomality or Molarity of the Potassium Permaganate?

very good.

Why did you add the sulfuric acid to the solution? Wouldn't the reaction work without it, if you're determining concentration of H2O2? Or is Sulfuric acid the contaminant to your H2O2 solution?

does anyone know how much sulfuric acid to add for a certain amount of H2O2?