Tuesday, December 20, 2011

The sad state of science

This post illustrates in so many ways what is wrong with our world today. To continue stereotyping, and to continue to engrave the idea of blatant consumerism rather than real discovery and science simply disturbs me on so many levels.

I couldn't agree more with Bree. We should cultivate the culture of discovery in all kids, whether they are boys or girls. Arguably, one of the most significant discoveries in the 20th century was made by a woman, and that discovery brought about the nuclear age. (Whether it was a good thing or a bad thing is another matter all-together. That's what the governments did with the discovery...) which among other things helped broaden our understanding of physics, brought about a powerful new source of energy, and gave us life-saving cancer treatments.

Mock Ramblings

Some shameless promotion of a friend's blog:

Mock Ramblings

He's a writer, and posts some rather clever series. If you haven't read any of his writing, you really should! It's good. Real good. One of my favorite (though they haven't made an appearance recently) is Reflections of a Deranged Cultist. Formatted as hijacked blog postings, the deranged cultist, and no sometimes his love interest make postings about the goings on in a secret Cthulhu worshiping cult. What could be more fun? A steel sphere filled with angry porcu-bats, that's what!  

Wednesday, December 07, 2011

Lab Notes: Elemental Iodine - wrap up

In my previous experiment I extracted elemental iodine from Tincture of Iodides. Now to explore how it happens. I knew that the mixture of hydrogen peroxide and hydrochloric acid caused elemental iodine to precipitate from the solution, but didn't understand the mechanism. Now, after a bit of exploring and research, I understand the reaction mechanism. Starting with what is known:

You can see the potassium is left as a positive ion, as the iodine is no longer combined with it. Also note the Iodine was in the -1 oxidation state, but is now in the 0 oxidation state. This means it has been oxidized, not reduced. So, an oxidizer is needed to move the state up one. Hydrogen peroxide is readily available, and at low concentrations is relatively safe to work with. No oxygen was evolved in the reaction between the hydrogen peroxide and potassium iodide, so what is hydrogen peroxide reduced to?

Water and an oxygen radical? Not quite. I'll get to why in a moment.Since no oxygen is evolved from this reaction, I know that oxygen is not generated, so the hydrogen peroxide must be reduced to water. In order for that to occur, there must be hydrogen ions available to balance the equation. So, this pair of half-reactions is most likely:

Adding an acid allows the hydrogen peroxide to decompose to 2 water molecules. After combining the 2 equations, you obtain this equation:

Which is the mechanism behind the reaction. It is a redox reaction, where the Iodine is oxidized, and the hydrogen peroxide is reduced. In my reaction I used hydrochloric acid, so putting everything together, this is the resulting reactants and products:

As you can see, the result is elemental iodine precipitating out of a solution of potassium chloride.

Tuesday, December 06, 2011

Lab Notes: Iron Oxides

For fun, I had this idea: the classic grade-school experiment: making rust. Good ol' iron oxide. So, I grabbed a small row of staples, added some salt, and dropped them in the water.... and waited.

I'm not the most patient person in the world, so I grew tired of how long it was taking to turn steel into rust. Thinking to myself, "Hydrogen peroxide is an oxidizer, therefore, hydrogen peroxide should make the rust faster", and it did. What I ended up with was iron hydroxide, no iron oxide, but with heat it dehydrates, which yielded the black iron oxide, magnetite. Not surprisingly, it's magnetic and quite fun to play with, but it wasn't what I was after, I wanted the deeply red Iron (III) Oxide. When rust forms, it's a mix of oxides and hydroxides. I was hoping to separate the two by somehow driving one into solution, while leaving the other alone. The idea occurred to me by way of a mistake. I had a vial of what was left over after attempting to get a purer form of acetic acid through heat distillation, instead of grabbing the empty vial, I grabbed that one instead, pouring  the magnetic iron oxide into that instead of an empty vial. I noticed that the brown portion was gone, leaving behind only the black. I also noticed that the solution took on a very strong orange coloration. So, I set out to attempt this. Reacted more of the oxide with vinegar (acetic acid), and filtered. To my surprise what came out was a stunningly bright orange solution. What I'm not sure of right now is if it is iron acetate, or iron oxide dissolved in acetic acid. I'm in the process of evaporating the liquid from the solution, and I will see what I get when I rinse the dry product with water.

On another note about the oxidation with hydrogen peroxide, it seems to go much faster with the introduction of sodium chloride (table salt), I don't know the mechanism behind this, but it was very interesting to observe.