We going to start today by preparing a useful reagent, carbamide peroxide.

This is effectively urea which has been crystallized in the presence of hydrogen peroxide.

Instead of the crystals forming a water-hydrated salt, they trap hydrogen peroxide instead of form of solid adduct.

We're starting off with 66 grams of urea crystals.

We've placed these into a 250 milliliters beaker.

Now we've weighed out 150 grams of a strong hydrogen peroxide solution.

Now we've weighed out 150 grams of a strong hydrogen peroxide solution.

We know that it's between 25 and 30 percent concentration.

So approximately the same number of moles as urea.

Now we add the peroxide solution to the solid urea crystals in the beaker.

Even at room temperature you can see a lot of urea is going to dissolve.

Let's give it a stir.

Now, we're going to heat this up in order to get all the urea to dissolve.

Easiest way to do this is to use medium power in a microwave oven for a minute or so.

The urea dissolves pretty quickly and you can see some slight effervescence as the heat

evaporating the decomposition of the hydrogen peroxide into oxygen.

The temperature of the liquid is 75 to 80 degrees C.

So now we'll place this in a freezer and chill it down to around 0 degrees C.

It's now somewhere around 5 degrees and you can already see large sharp like translucent

crystals growing in the solution as it cools.

Continue cooling the mixture for a further hour.

Don't allow it to freeze.

You can see that there's now quite a large crystal mass in the solution.

Set up for filtration and filter the crystals from the still cold liquid.

Don't wash the crystals, but let them dry fully on the pump.

Here's our first batch of crystals.

46g of our duct.

As you can see, the crystals are really long and beautiful.

To prove they're not just urea, let's apply a drop of a water suspension containing manganese

dioxide.

As you can see the crystals themselves melt and react very vigorously.

This is the first batch of crystals.

This is the catalysis of the hydrogen peroxide that they contain into oxygen.

We saved the filtrate and chilled it down for a further hour in the freezer.

We obtained another batch of the sharp like crystals as you can see.

As before, we filtered and dried these on the pump and combined them with our previous batch.

And here's our combined product.

80g of urea hydrogen peroxide crystalline duct.

This is a 77% yield on our starting urea and hydrogen peroxide, which is not bad.

Carbamide peroxide is a reagent which offers the oxidizing power of very concentrated hydrogen

peroxide, but with a lot less risk in terms of handling.

It is also used in DIY tooth bleaching preparations.

Thanks for watching and stay tuned because we've got some plans for this reagent.

See you next time.