I’m watching Moon Machines (yet again), and they mentioned that lithium hydroxide was used to scrub the excess carbon dioxide from the air aboard the spacecraft. In one of those ‘I think I’ll see how that works’ moments, I immediately saw that lithium hydroxide and carbon dioxide make lithium carbonate and water:
2LiOH + CO[sub]2[/sub] => H[sub]2[/sub]O + Li[sub]2[/sub]CO[sub]3[/sub]
OK, it balances. Each side has two lithiums, four oxygens, two hydrogens, and one carbon. I know that the products are H[sub]2[/sub]O and Li[sub]2[/sub]CO[sub]3[/sub]. But what’s actually going on in the reaction?
Here’s what I’m thinking: CO[sub]2[/sub] molecules find LiOH molecules. They say, ‘Hey, that looks like a good gig. Let’s move in and kick lame-o Hydrogen out!’ Lithium has a (+) charge, and carbonate has a (2-) charge, so to make lithium carbonate you need two lithiums (and another oxygen). If you have two lithiums, you also get two oxygens and two hydrogens. So CO[sub]2[/sub] joins up with Lithium and kicks Mr. Hydrogen and Mr. Hydrogen to the street. Taking a cue from I, Mudd, CO[sub]2[/sub] looks at Oxygen and Oxygen and says, ‘I love you. However, I hate you,’ and kicks one of the Oxygen twins out. So now we have two hydrogens and an oxygen standing at the curb saying, ‘You bastard!’ They all look at each other and say, ‘We don’t need them! Let’s get our own place!’ And there’s your water.
Do I have that right? I’m not feeling entirely well today, and my mind is moving slowly.