Fulmen
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Bicarbonate to carbonate; strange low yield?
So I needed a bunch of sodium carbonate, and I calculated that it would be cheaper to start with sodium bicarbonate. According to Wikipedia 200°C should do nicely:
2 NaHCO3 => Na2CO3 + CO2 + H2O
I started with 550g, and my math tells me I should expect a yield of 405g. So why did I only get 355g? The bicarbonate was perfectly dry, and I can
not find any data on any hydrates.
We're not banging rocks together here. We know how to put a man back together.
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davidfetter
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Many things could account for what you see, to include:
- "Dry" is harder to assess than you may think.
- Scales are not always quite as accurate over their entire range as you may be assuming.
- (unlikely) You got spots so much hotter that you may have NaOH.
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Texium
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Or... you did your math wrong.
550 g bicarbonate / 84 g/mol = 6.55 mol
6.55 / 2 = 3.27 mol carbonate expected
3.27 mol * 105.99 g/mol = 347 g sodium carbonate
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Texium
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Thread Moved
1-3-2025 at 08:52 |
bnull
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405 g? Let's see.
2 moles of NaHCO3 = 2*84=168 g
1 mole of Na2CO3 = 106 g
550 g/168 g=3.27
3.27*106 g=347 g
| Quote: | | So why did I only get 355g? |
Because you didn't heat it for long enough.
Edit: Try this: Balance Chemical Equation.
[Edited on 1-3-2025 by bnull]
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Fulmen
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Nope, apparently I did it wrong 3 times! Jeeez, I'm getting soft.
Edit: I found it. My bicarbonate was carbon neutral with a molar weight of 72 :-D
@ bnull: We're within the limits of kitchen chemistry and scales here. But I did notice a bit of low solubility material in it so
you're probably right. Not that it matters, I'm just making sodium nitrate from calcium nitrate. The bicarbonate should do the same job, but it's low
solubility and CO2 generation would make for a messy reaction.
[Edited on 1-3-25 by Fulmen]
We're not banging rocks together here. We know how to put a man back together.
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bnull
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At least you didn't spend almost an hour trying to find the derivative of ef(x) and wouldn't trust the result even after seeing it in a
calculus book.
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