Question

potassium bromide and calcium sulfide
express your answer as a chemical equation. enter noreaction if no precipitate is formed. identify all of the phases in your answer.
a chemical reaction does not occur for this question.
submit previous answers request answer
incorrect; try again; 2 attempts remaining

Explanation:

Step1: Write the chemical formulas

Potassium bromide is \(KBr\) (aqueous, \(aq\) phase as it is soluble), calcium sulfide is \(CaS\) (aqueous, \(aq\) phase as it is soluble).

Step2: Predict the double - displacement reaction

In a double - displacement reaction \(AB + CD
ightarrow AD+CB\). Here, \(A = K^{+}\), \(B=Br^{-}\), \(C = Ca^{2 +}\), \(D = S^{2-}\). The products would be \(K_{2}S\) (soluble, \(aq\) phase) and \(CaBr_{2}\) (soluble, \(aq\) phase).
Since all the products (\(K_{2}S\) and \(CaBr_{2}\)) are soluble in water (based on solubility rules: sulfides of group 1 metals (\(K^{+}\) is in group 1) are soluble and bromides of most metals (including \(Ca^{2+}\)) are soluble), no precipitate is formed.

Answer:

\(2KBr(aq)+CaS(aq)
ightarrow K_{2}S(aq)+CaBr_{2}(aq)\) (or we can write "noreaction" as no precipitate is formed)