3

I am teaching two young boys (elementary school) some basics about chemistry, but I have to learn as I go myself.

Is this a viable model to explain oxidation and fire? When we light up the fireplace, oxygen "steals" electrons from the wood, which is carbon. But carbon won't let oxygen just leave with its electron(s), so this theft results in them clinging together, and we call that Co2.

At the moment they cling together, their tight grip gives off heat. We call this an exothermic reaction. This word may not be easy to remember, but think of "exhaust pipe" (going out, so "exo") and "thermos" (it stores something hot). So when you hear exothermic reaction you know it's a reaction that gives off heat.

And how much energy is required to get oxygen and carbon to let go of their tight grip? Exactly the same amout of thermic energy they gave off when they first clung together!

Gelb
  • 153
  • 3
  • Why don you need that much to talk about electron in the first place? We had basic chemistry in elementary school, and no one was particularly puzzled by the basic concepts. – Greg Nov 11 '17 at 06:44
  • 2
    This interview with Feynman pretty much does the job. Since I've got nothing else to add to it, I've posted it here as a comment (instead of a full-fledged answer). O:) – paracetamol Nov 11 '17 at 08:30
  • @Greg. I've purchased a chemistry set for kids and I am going over everything with them. To get through it the concept of the electron must be introduced. – Gelb Nov 11 '17 at 12:45
  • @paracetamol. When you say you have nothing else to add, I'm assuming there were no blatant errors in my model? I just made it up, and I'm a complete neophyte in chemistry. Thanks a lot for the video! – Gelb Nov 11 '17 at 12:46
  • related https://chemistry.stackexchange.com/questions/1254/what-are-the-chemical-reactions-behind-fire – Mithoron Nov 11 '17 at 17:09
  • 1
    @Gelb You don’t need to introduce all the concepts, electrons, oxidation, bonds, heat etc in the same time just because it was said in a box – Greg Nov 11 '17 at 17:12
  • I feel it's not exactly important if it's "correct". Everything in our description of real world is just a model, illusion that we truly understand, how things work. More to the point, there no "electron grabbing" and there's no reason to approximate wood with pure carbon, if you can simply tell about burning pure carbon... – Mithoron Nov 11 '17 at 17:16
  • @Gelb Ah no, I meant I had nothing else to add to the video. Also, I'd go with what Greg said: You don't have to introduce everything to them at once... take it slow ;) [As for your "model", nope, no blatant errors] – paracetamol Nov 11 '17 at 17:44
  • There is no need to even mention esothermic – Alchimista Nov 11 '17 at 19:50
  • @paracetamol. Thanks a million. You also gave me some outstanding entertainment on YouTube. – Gelb Nov 11 '17 at 21:40
  • @Mithoron. That's true, burning pure carbon would be easier. But I will talk about it when we put logs of wood in the fireplace. If I had some coal lying around, I suppose we would have used that. But when you say "there no "electron gramming"", what you do mean by that Mithoron? Is there are a blatant error in the model after all? I like the proverb "a model is a lie that helps you see the truth", but I don't want to tell blatant lies to the kids. – Gelb Nov 11 '17 at 21:40
  • Oh, well... maybe you could put it like that, but it's quite metaphorical. Also as wood is made of carbohydrates (besides other stuff) you could say that carbon is oxidated and water "liberated" from structure. – Mithoron Nov 11 '17 at 22:26
  • On the other hand it seems to be the clue of your other question, grabbing, losing, stealing etc. might be tolerable as metaphor, but are no good for defining this process. – Mithoron Nov 12 '17 at 02:12
  • @Mithoron It was Karl who told me in the comments that oxidize behaves like other verbs, and layed out the example "Joe hit Bill". So therefore I just updated the oxidize question. But I am still none-the-wiser with regards to how the verb "oxidize" behaves. I thought the chemistry forum knew more about grammar than the grammar forum knew about chemistry. So, it would be here the expertise was. Alchimista told he was a bit befuddled by it himself in French. Anyway, thanks for your comments. They have made a big difference. – Gelb Nov 12 '17 at 14:42

0 Answers0