Question

What is the final concentration of the solution produced when 225.5 mL of a 0.09988-M solution of Na₂CO₃ is allowed to evaporate until the solution volume is reduced to 45.00 mL?

a) 0.499 M
b) 0.248 M
c) 1.247 M
d) 2.495 M

Answer 1

The final concentration of the Na₂CO₃ solution after evaporation to 45 mL is 0.499 M, calculated using the principle of conservation of moles.

Step-by-step explanation:

The final concentration of the solution when a 225.5 mL of a 0.09988-M solution of Na₂CO₃ is allowed to evaporate until the volume is reduced to 45.00 mL can be calculated using the principle of conservation of moles. Since no solute is removed or added during the evaporation process:

M1 × V1 = M2 × V2

Where M1 is the initial molarity, V1 is the initial volume, M2 is the final molarity, and V2 is the final volume.

Thus, we can solve for M2:

M2 = (M1 × V1) / V2 = (0.09988 mol/L × 225.5 mL) / 45.00 mL

This calculation results in a final molarity (M2) of 0.499 M, which corresponds to option a).