Final answer:
The mass balance equation for a 0.025M Na2CO3 solution is [Na+] = 2[Na2CO3] and [CO32-] = [Na2CO3], resulting in [Na+] = 0.05M and [CO32-] = 0.025M. The charge balance equation is 2[Na+] = [CO32-], confirming the neutrality of the solution.
Step-by-step explanation:
To write the mass balance and charge balance equations for a 0.025M Na2CO3 solution, one must consider the dissociation of sodium carbonate in water. Sodium carbonate dissociates into two sodium ions (Na+) and one carbonate ion (CO32-).
The mass balance equation reflects the stoichiometry of the dissociation reaction, while the charge balance equation reflects the neutrality of charge in the solution. Since Na2CO3 completely dissociates in water, the mass balance would be represented by [Na+] = 2[Na2CO3] and [CO32-] = [Na2CO3], given that the initial concentration of Na2CO3 is 0.025M. Therefore, we have [Na+] = 2(0.025M) = 0.05M and [CO32-] = 0.025M. The charge balance equation is based on the principle that the sum of the positive charges must equal the sum of the negative charges. For Na2CO3 in water, this gives us 2[Na+] = [CO32-]. Substituting the concentrations, we get 2(0.05M) = 0.025M, which simplifies to 0.10 = 0.025. This confirms charge balance since both sides reflect the neutrality of the solution.