Textbook Practice Problem F3
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Textbook Practice Problem F3
I'm confused on how to write formulas for acids, for instance, on problem F3 in the textbook it asks you to write the formula for nitric acid. I understand the general rule is that acids start with hydrogen, but I'm confused on how it is HNO3. Does anyone know how to get the NO3 part? Or are there just some key acids that I should have memorized?
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Re: Textbook Practice Problem F3
Maleeha Zaman 1K wrote:I'm confused on how to write formulas for acids, for instance, on problem F3 in the textbook it asks you to write the formula for nitric acid. I understand the general rule is that acids start with hydrogen, but I'm confused on how it is HNO3. Does anyone know how to get the NO3 part? Or are there just some key acids that I should have memorized?
Hello Maleeha,
Your statement that acids start with hydrogen is correct. Another rule of thumb is that binary acids contain two elements and therefore, they are names hydro-____-ic acid (e.g. Hydrochloric Acid). For most other acids, common names are used instead of standard chemistry nomenclature (e.g. vinegar) and therefore cannot be deduced from their formula. A few key acids to memorize are the following: H2SO4 = Sulfuric acid; HNO3 = Nitric Acid; and HC2H3O2 = acetic acid. I initially had trouble with designating names for acids as well and this video helped solidify my understanding: https://www.youtube.com/watch?v=7OMSa6C7sFQ. :)
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Re: Textbook Practice Problem F3
Hi Maleeha!
Acids are named based on their anion. Nitric acid has the suffix -ic, indicating that a nitrate (NO3-) rather than a nitrite (NO2-) ion is being used. The suffix "-ic" is used for acids with any polyatomic ions that end in "-ate". In contrast, the suffix "-ous" is used in the acid name for acids with polyatomic ions ending in "-ite". The nitrite ion (NO2-) forms the acid HNO2, or nitrous acid.
Acids are named based on their anion. Nitric acid has the suffix -ic, indicating that a nitrate (NO3-) rather than a nitrite (NO2-) ion is being used. The suffix "-ic" is used for acids with any polyatomic ions that end in "-ate". In contrast, the suffix "-ous" is used in the acid name for acids with polyatomic ions ending in "-ite". The nitrite ion (NO2-) forms the acid HNO2, or nitrous acid.
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Re: Textbook Practice Problem F3
Nick the Camel ate a Clam for Supper in Pheonix
With this mnemonic, you can remember the -ate polyatomic ions for Nitrogen, Carbon, Chlorine, Sulfur, and Phosphorus. I'll show Nitrogen (nitrate) as an example:
1. Nick has one vowel, so nitrate has a charge of negative one.
2. Nick has three consonents, so nitrate has three oxygen atoms.
3. Therefore, nitrate is NO3-
If you want -ite ions instead, keep the charge but lose an oxygen atom.
A lot of acids have hydrogen and then a polyatomic ion. -ic usually means the -ate ion and -ous usually means the -ite ion as Elaine points out. With that in mind you can figure out nitric acid, phosphoric acid, sulfuric acid, etc. It's just the ion and then as many hydrogens as you need to "counter" the ionic charge and get a neutral charge on the acid molecule. You can also note that hydro- indicates a binary acid like Justin said, it only has a monoatomic ion following instead of a polyatomic ion (so hydrochloric acid uses the chloride Cl- ion and is HCl, while chloric acid would use the chlorate ion and be HClO3). A lot of the other ones like acetic acid you'll just have to memorize, but if you just work with it long enough it'll stick no problem!
With this mnemonic, you can remember the -ate polyatomic ions for Nitrogen, Carbon, Chlorine, Sulfur, and Phosphorus. I'll show Nitrogen (nitrate) as an example:
1. Nick has one vowel, so nitrate has a charge of negative one.
2. Nick has three consonents, so nitrate has three oxygen atoms.
3. Therefore, nitrate is NO3-
If you want -ite ions instead, keep the charge but lose an oxygen atom.
A lot of acids have hydrogen and then a polyatomic ion. -ic usually means the -ate ion and -ous usually means the -ite ion as Elaine points out. With that in mind you can figure out nitric acid, phosphoric acid, sulfuric acid, etc. It's just the ion and then as many hydrogens as you need to "counter" the ionic charge and get a neutral charge on the acid molecule. You can also note that hydro- indicates a binary acid like Justin said, it only has a monoatomic ion following instead of a polyatomic ion (so hydrochloric acid uses the chloride Cl- ion and is HCl, while chloric acid would use the chlorate ion and be HClO3). A lot of the other ones like acetic acid you'll just have to memorize, but if you just work with it long enough it'll stick no problem!
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