Question

Determine the concentration of NO−3 in each aqueous solution. (Assume complete dissociation of each compound.)

0.24 M KNO3

Express your answer using two significant figures.

0.24 M Ca(NO3)2

Express your answer using two significant figures.

0.24 M Cr(NO3)3

Express your answer using two significant figures

Answer 1

1. Let us write the dissociation reaction

        KNO₃ -----> K⁺ + NO₃^-

As can be seen from the above reaction

1 moles KNO₃= 1 moles NO₃^-

Hence Concentration of NO₃^-= Concentration of KNO₃=0.24M

Concentration of NO₃^- in aqueous solution of 0.24 M KNO₃ is 0.24 M

2. Let us write the reaction in ionic form

Ca(NO₃)₂ ----------> Ca²⁺ 2 (NO)^3-

From the above equation we can see that

1 moles of Ca(NO₃)₂ = 2 Moles of (NO)^3-

Hence of concentration of (NO)^3- = 2 * concentration of f Ca(NO₃)₂ = 2*0.24 = 0.48 M

Concentration of NO₃^- in aqueous solution of 0.24 M Ca(NO₃)₂ is 0.48 M

3. Let write the equation in ionic form

Cr(NO₃)₃ -------> Cr³⁺ + 3(NO₃)^-

As can be seen from above reaction

1 moles Cr(NO₃)₃ = 3 moles of 3(NO₃)^-

Hence concentration of (NO₃)^- = 3* concentration of Cr(NO₃)₃ = 3*0.24 = 0.72 M

Concentration of NO₃^- in aqueous solution of 0.24 M Cr(NO₃)₃ is 0.72 M