Determine the concentrations of na2co3, na , and co32– in a solution prepared by dissolving 2.35 × 10–4 g na2co3 in 2.00 l of water. express all three concentrations in molarity. additionally, express the concentrations of the ionic species in parts per million (ppm). note: determine the formal concentration of co32–. ignore any reactions with water.

The concentration in terms of molarity is calculated by dividing the number of moles by the volume of liters of the solution. The molar mass of Na2CO3 is equal to 105.99 g/mol. The concentration of the compound is equal to,

     M = (2.35 x 10^-4 g/ 105.99 g/mol) / (2 L)
     M = 1.109 x 10^-6 M

The concentrations of the ionic species:
  
Na

There are 2 moles of Na in Na2CO3 hence, the concentration of this ionic species is equal to twice of the calculated concentration above.

    M2 = (1.108 x 10^-6 M)(2)
     M2 = 2.217 x 10^-6 M

CO32-

In the chemical symbol given above, there is only 1 mole of CO32- in the equation such that the concentration is equal to the concentration of the compound.

     M3 = 1.109x 10^-6 M

The answer is letter c