In each of the following groups, identify the two substances whose aqueous solutions have common properties to a marked degree by circling the two formulas. Explain why you made your choice.

I'm not the two formulas I circle is correct. Below are my explanations. Fix me where I am wrong. I appreciate your help!

a) CuS, CuCl2, Na2S, KCl

I know CuS, copper (II) sulfide is insoluble, but CuCl2,copper (II) chloride, Na2S, Sodium Sulfide, and KCl, Potassium Chloride, are soluble. The two out of the three (in which I will circle) I see common characteristics are CuCl2 and KCl, since they both have cations of Cl^-.

b) HCl, HC2H3O2, NaC2H3O2

I'd circle HCl, hydrochloric acid, and NaC2H3O2, Sodium Acetate, because they are strong electrolytes.

4 answers

I don't see anything wrong with your answers; however, I think it is a poor question. For example, in question (a), why not include Na2S since that is soluble along with CuCl2 and KCl. All three are quite soluble so I would say that was to a marked degree. KCl and CuCl2 DO have the Cl^- as common ions.
For question (b), you are correct that HCl and NaC2H3O2 are strong electrolytes ( but only in solution), but why not include NaC2H3O2 and HC2H3O2 because both contain the acetate ion (although not to a marked degree (and to what extent is a "marked degree"?) since acetic acid is only slightly ionized). HCl with no (aq) after it or something to indicate it is solution, is a gas and is not ionized. Or could HCl and HC2H3O2 both contain hydrogen atoms. I just don't think these are good questions at all.
I hope I've not confused you.
opps I forgot to add NH4C2H3O2 to the list of substances for part (b)

a) CuCl2 and KCl - both soluble and have chlorine ion as anion.

b) NH4C2H3O2 and NaC2H3O2 - both soluble and have acetate ion as anion
SO3 can be produced in the following two-step process:

FeS2 + O2 ---> Fe2O3 + SO2
S02 + O2 ----> SO3

Assuming that all the FeS2 reacts, how many grams of SO3 are produced when 20.0 g of the FeS2 reacts with 16.0 g of O2?
Katrina-
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