Chemical Formulas

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nayha a 1E
Posts: 96
Joined: Wed Sep 30, 2020 9:54 pm

Chemical Formulas

Postby nayha a 1E » Wed Nov 04, 2020 11:59 pm

Are we supposed to already know the chemical formulas of substances/molecules? For example, a question on the week 5 sapling homework asks for the structure of a carbamate ion. This example already had a Lewis structure to work off of, but will they always? Or will we just have to know?

Sydney Lam_2I
Posts: 90
Joined: Wed Sep 30, 2020 10:09 pm

Re: Chemical Formulas

Postby Sydney Lam_2I » Thu Nov 05, 2020 12:06 am

Hi,

I know that in high school I had to memorize the ions and how to create molecular formulas, but I don't know if Dr. Lavelle specifically said if we had to know them already. I would try to start memorizing the most common ones just in case!

connie ma 3G
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Re: Chemical Formulas

Postby connie ma 3G » Thu Nov 05, 2020 12:20 am

Like someone else said, there is a list of common polyatomic ions that are helpful to know just because they are so commonly used/seen. I think most high school chemistry classes make you memorize them. Other than that, I think the formulas for the more uncommon compounds are normally given to us.

Jamie Wang 3C
Posts: 106
Joined: Wed Sep 30, 2020 9:51 pm

Re: Chemical Formulas

Postby Jamie Wang 3C » Thu Nov 05, 2020 12:30 am

Does anyone have any memorization tricks for them? I find myself memorizing them for the semester/year and then completely forgetting about it later.

Lindsey_Su_3A
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Re: Chemical Formulas

Postby Lindsey_Su_3A » Thu Nov 05, 2020 8:43 am

Also on the Sapling questions we were expected to know the formulas for nitrite and phosphite. We didn't really go over naming ions in class so I was wondering if we also had to know formulas for all ions?

Ariel Guan 1H
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Re: Chemical Formulas

Postby Ariel Guan 1H » Thu Nov 05, 2020 12:43 pm

I feel like we will be expected to memorize the common polyatomic ions, or at least those would be good to know. So nitrate, nitrite, phosphate, phosphite, hydroxide, etc. would probably be good to know.

Grace_Remphrey_2J
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Re: Chemical Formulas

Postby Grace_Remphrey_2J » Thu Nov 05, 2020 2:18 pm

I think as long as you have the common ones memorized, you should be fine! So far, that has been what my TA and Lavelle have said. Just be sure to double-check with your TA just in case!

Pranav Daggubati 3C
Posts: 109
Joined: Wed Sep 30, 2020 9:35 pm

Re: Chemical Formulas

Postby Pranav Daggubati 3C » Thu Nov 05, 2020 3:48 pm

Most common polyatomic ions have easily memorizable formulas/structures due to patterns. Naming conventions are used to determine these patterns. For example, in the case of nitrate and nitrite, the -ate suffix refers to the ion with one more oxygen than the -ite suffix. For oxyanions of halogen (perchlorate, bromate, iodite), the naming convention is easily shown: per- > -ate > -ite > hypo-. For other ions, like ammonium or hydronium, the -nium suffix refers to the extra hydrogen on ammonia and water.

Jonathan Batac - 2D
Posts: 99
Joined: Wed Sep 30, 2020 10:03 pm

Re: Chemical Formulas

Postby Jonathan Batac - 2D » Thu Nov 05, 2020 4:16 pm

There doesn't seem to be a clear requirement to memorize all the molecules and compounds that Lavelle uses, but it is very useful to memorize quite a bit of them. For example, theres a big difference between nitrate and nitrite. I personally think everyone should know how to derive a chemical formula from the name and vice versa.


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