Expressing the Concentration of an Electrolyte

When an ionic compound dissolves, the relative concentrations of the ions in the solution depend on the chemical formula of the compound. For example, a 1.0 M solution of NaCl is 1.0 M in Na ions and 1.0 M in CF ions, and a 1.0 M solution of Na2S04 is 2.0 M in Na ions and 1.0 M in 804 ions. Thus, the concentration of an electrolyte solution can be specified either in terms of the compound used to make the solution (1.0 M Na2S04) or in terms of the ions in the solution (2.0 M Na and 1.0 M 804 ). 

What is the molar concentration of each ion present in a 0.025 M aqueous solution of calcium nitrate  

Analyze We are given the concentration of the ionic compound used to make the solution and asked to determine the concentrations of the ions in the solution. 

Plan We can use the subscripts in the chemical formula of the compound to determine the relative ion concentrations. 

Check The concentration of NO3 ions is twice that of Ca ions, as the subscript 2 after the NOs in the chemical formula Ca(N03)2 suggests it should be. 

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