Fundamental F17

[Jessy Ji 2J]

After I figure out the empirical or molecular formula, how do I know in which order do I write the elements in my answer? For example in the question below, I figured out the empirical formula to be OsC4O4, how do I know that if I should write it as C4O4Os, O4C4Os ect...

Osmium forms a molecular compound with mass percent- age composition 15.89% C, 21.18% O, and 62.93% Os. (a) What is the empirical formula of this compound? (b) From the mass spectrum of the compound, the molecule was determined to have a molar mass of 907 g?mol21. What is its molecular formula?

[emily3L]

For empirical and molecular formulas, you write Carbon first, then Hydrogen, then in alphabetical order. Ionic compounds, oxides, hydroxides, and acids are exceptions.

[Irene Kang 3F]

You should read Fundamental D Nomenclature in the textbook for more information about how to write chemical formulas and how the naming systems differ.

Also, I think in a different post he wrote that the order doesn't matter and that anything counts as long as the numbers and elements are correct.

[Sanjana Sivakumar 2E]

For empirical and molecular formulas, you write Carbon first, then Hydrogen, then in alphabetical order. Ionic compounds, oxides, hydroxides, and acids are exceptions.

I know we haven't learned this yet, but to continue off of what Emily said:

For ionic compounds: you write the cation (positive ion) first and then the anion (negative ion).
For oxides: you end with O.
For hydroxides: you end with with OH.
For acids: you start with H.