Figuring Out State Symbols

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Isabella Dal Porto 1H
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Joined: Fri Aug 30, 2019 12:16 am

Figuring Out State Symbols

Postby Isabella Dal Porto 1H » Wed Oct 02, 2019 11:03 pm

It has been awhile since I have taken chemistry. I was just wondering if symbols for whether or not a reactant or product is aqueous, liquid, solid, or gas can be identified by looking at the molecular formula alone or if you need to know the chemical properties of the reactant or product to determine it?

Anish Patel 4B
Posts: 59
Joined: Thu Jul 11, 2019 12:17 am

Re: Figuring Out State Symbols

Postby Anish Patel 4B » Wed Oct 02, 2019 11:13 pm

From my experience, common compounds (such as acids/bases, gases, and salts) and reactions (combustion) are usually easily identifiable based on their molecular formula. For example, acids/bases are aqueous in a solution with water while all reactants/products in a combustion reaction are gases. Also, you can try and remember certain solubility rules to determine whether compounds produce solids or aqueous compounds in a reaction. I also think that if a problem deals with multiple different states of matter they will tell you the conditions in which the reaction is taking place so you can more easily decide what the proper states should be.

Aadil Rehan 1D
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Re: Figuring Out State Symbols

Postby Aadil Rehan 1D » Wed Oct 02, 2019 11:30 pm

It's also good to keep the diatomic elements in mind - can be remembered with the abbreviation "HOFBrINCl" (Hydrogen, Oxygen, Fluorine, Bromine, Iodine, Nitrogen, Chlorine.) Apart from special cases of pressure and/or temperature, when you see a pure form of one of these elements, it should always be gaseous and diatomic.

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Joined: Wed Sep 18, 2019 12:20 am

Re: Figuring Out State Symbols

Postby Varadhan_3G » Wed Oct 02, 2019 11:38 pm

I'm not sure it will always be possible to determine the states. Like Isabella said, you can look at the molecular formula for common compounds and use rules such as pure acids being liquids, and when the word 'insoluble' is used adjacent to a compound we can assume that compound to be a solid. Also for an acid to be aqueous (aq) that means it should be dissociated (E.g. HCL in H2O). Because states depend heavily on the context of the problem, there is often no way to memorize the states of compounds. I think they will either be given to us in the problem, or identifiable via the above methods. I know that in IB chemistry we had a data booklet with states for a few compounds. Will we have a data booklet in this class?

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