ACS Chemistry Practice Exam 2026 – The All-in-One Guide to Exam Success!

The equation used for the process of dilution is represented by the relationship \( C_1V_1 = C_2V_2 \). This equation establishes that the product of the initial concentration (\( C_1 \)) and the initial volume (\( V_1 \)) of a solution is equal to the product of the final concentration (\( C_2 \)) and the final volume (\( V_2 \)).

This relationship reflects the principle of conservation of mass, where the amount of solute remains constant before and after dilution. When you dilute a solution, you are adding more solvent, which increases the total volume while decreasing the concentration of the solute. Therefore, the initial concentration times the initial volume must equal the final concentration times the final volume, allowing for the calculation of any one variable if the others are known.

The other choices refer to different concepts. The second choice, which adds concentrations and volumes, does not accurately represent any fundamental chemistry principle relevant to dilution. The third option appears to rearrange the equation incorrectly and does not align with the principles of dilution. The last choice describes the relationship of moles of solute, volume, and molarity, but it is not specific to the process of dilution.