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Topic: PbCO3  (Read 14795 times)

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Offline FouRRaW

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PbCO3
« on: February 14, 2007, 09:20:57 PM »
How do you know that PbCO3 is a solid?
I'm supposed to write out the total net ionic equation of Pb(NO3)2(aq) and Na2CO3.

And i know that when double replacement happens PbCO3 is a solid but the other is aqueous, because my teacher said so?
Why is it a sold, how do you know it is a solid and how do you figure it out when doing a net ionic equation?

Anybody know? Help Appreciated, thanks.

Offline constant thinker

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Re: PbCO3
« Reply #1 on: February 14, 2007, 09:32:27 PM »
Start with a regular balanced equation.

You already know you have:
Pb(NO3)2 (aq) + Na2CO3 (aq) -->

You said it was double displacement, which it is. The products shouldn't be heard to predict. You also already know that one of your products is PbCO3, and that it will be your precipitate (the solid).
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Offline FouRRaW

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Re: PbCO3
« Reply #2 on: February 14, 2007, 09:48:30 PM »
okay, i'm just wondering how my teacher knew that PbCO3 was a solid?

(oh and in the original question both compounds are aqueous)

Offline constant thinker

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Re: PbCO3
« Reply #3 on: February 14, 2007, 09:51:05 PM »
A lot of lead compounds are insoluble I believe. He probably found out originally from looking a solubility table. They're really useful.
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Offline FouRRaW

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Re: PbCO3
« Reply #4 on: February 14, 2007, 09:53:05 PM »
okay, so there was no way of figuring it out in your head? Or could you some how figure out that PbCO3 is insoluble?

Offline Yggdrasil

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Re: PbCO3
« Reply #5 on: February 14, 2007, 09:56:54 PM »
AFAIK, the only way you could know that PbCO3 is insoluble is by looking it up in a solubility table.  It's one of those things in chemistry that's been determined purely empirically.

By the way, if anyone has a more theoretical explanation of why certain salts are soluble which can predict solubility, I'd love to hear it.

Offline FouRRaW

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Re: PbCO3
« Reply #6 on: February 14, 2007, 09:58:05 PM »
Thank you so much, what does AFAIK MEAN?

Offline Yggdrasil

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Re: PbCO3
« Reply #7 on: February 14, 2007, 09:58:56 PM »
AFAIK = as far as I know

Offline AWK

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Re: PbCO3
« Reply #8 on: February 15, 2007, 01:41:04 AM »
okay, i'm just wondering how my teacher knew that PbCO3 was a solid?

(oh and in the original question both compounds are aqueous)
Therer are some simple solubility rules come from chemist experirence, eg only carbonates od alkali metals (Li, Na, K Rb, Cs) and ammonia are soluble in water.
Search internet for solubility rules. They are quite simple if you know some inorganic chemistry and a periodic table
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