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Daniel Martinez 1k
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Joined: Wed Sep 18, 2019 12:16 am


Postby Daniel Martinez 1k » Wed Oct 02, 2019 4:51 pm

Question F3 part A asks "(a) Write the formula for nitric acid." Is this a formula that we are already supposed to know? If not, how does one know the formula without actually calculating the empirical/molecular formulas?

Tiffany Vo 3G
Posts: 52
Joined: Sat Aug 17, 2019 12:17 am


Postby Tiffany Vo 3G » Wed Oct 02, 2019 4:59 pm

I think you're technically supposed to know it because it is basically a nitrate ion (NO3-) with an added hydrogen atom. It tends to come up fairly often in chemistry, so it's really helpful to have it memorized. Assuming that the polyatomic ion that is being protonated ends with -ate (like nitrate), the acid would end in -ic (like nitric acid).

Kylie Lim 4G
Posts: 110
Joined: Sat Aug 17, 2019 12:15 am


Postby Kylie Lim 4G » Wed Oct 02, 2019 5:21 pm

I think it's assumed that we have the most common polyatomic ions and their charges memorized

Avnita C_4B
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Joined: Sat Sep 14, 2019 12:17 am


Postby Avnita C_4B » Wed Oct 02, 2019 5:45 pm

nitric acid falls under the table of memorizing specific ions and their acid/base compounds. Even if you do not perform the calculations for finding empirical formula, nitric acid is derived from the the combination of N and O, for which we have to memorize the ions. Then, you simply add H+ as it is an acid.

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