[samill2]

We're trying to answer the following question:

A solution has a concentration of 0.015 M of an unknown substance. If the solution has a pH of 8.3, which of the following describes the unknown substance:
a. strong acid
b. weak acid
c. strong base
d. weak base

We're at a loss and can't figure out what we're supposed to figure out without more information. My best guess is that we're trying to get the pH of the solute with the given information but we have not been able to figure out how to do that yet.

Thanks.

[Borek]

My best guess is that we're trying to get the pH of the solute with the given information but we have not been able to figure out how to do that yet.

pH? I guess you mean pKa here. If so - yest, that's more or less what you are trying to do, but actually you don't need to get into details. It is about simple elimination.

Can the acid solution have pH over 7?

What would be pH of 0.015 M solution of a strong base? What does it mean "strong" in this context? You actually don't even need to precisely calculate it, just a ballpark is perfectly enough.