Help with Pre-Lab questions! I have already looked at videos and it still doesn't make sense!

Question

When ionic solids dissolve in water, they produce soluble aqueous cations and anions. For example, adding MgBr₂ solids to water will produce ions according to the dissolution reaction below.

MgBr₂(s) → Mg²⁺(aq) + 2 Br⁻(aq)

                 cation        anion

In this lab, you will be observing the color of emission from ions dissolved in solution. Please write the dissolution reaction for each of the ionic solids below. (Use the lowest possible coefficients. Include states-of-matter under the given conditions in your answer.)

(a) NaNO₃

(b) BaCl2

(c) Ca(NO3)2

Answer 1

Simply "break" the salts into their component parts of cations and anions. The cations are the positive (+) species, and the anions are the negative (-) species. The (s) means solid and the (aq) means aqueous or dissolved in solution. Of course, these instructions presume that you know the charge (valence; oxidation state) of each element.

(a) NaNO₃(s) ==> Na⁺(aq) + NO₃^-(aq)

(b) BaCl₂(s) ==> Ba²⁺(aq) + 2Cl^-(aq)

(c) Ca(NO₃)₂(s) ==> Ca²⁺(aq) + 2NO₃^-(aq)