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chem p.59 - Q 5

Posted: Mon Nov 25, 2019 11:30 am
by mcatacct1
Could you elaborate on how I was suppose to interpret the table to eliminate each answer choice. I did not understand this.

Re: chem p.59 - Q 5

Posted: Mon Nov 25, 2019 2:35 pm
by NS_Tutor_Mathias
You know that calcium nitrate was added. You also know that nitrate can't really produce a precipitate (either from content, or get a good idea of this from the table). So you immediately know that your new precipitate must be formed with the calcium you added. From there you only have two options - calcium nitrate or calcium sulfate.

The former is what we just added in aqueous, not solid, form - which rules this out as an answer. Calcium sulfate in turn meets all the requirements: It is an actual solid and it is formed with calcium. This must be your precipitate.

While I would recommend reviewing solubility rules and memorizing them, usually just an idea of the major trends (nitrates are generally soluble, calcium likes to form white precipitates sometimes etc.) is usually plenty for the MCAT.