Original study example
Dissolve 0.10 mol of a substance to make 0.50 L of solution. Find the concentration and explain what changes if the final volume doubles.
Work through the example
Concentration is amount divided by volume: 0.10 / 0.50 = 0.20 mol/L. At 1.00 L with the same amount, it becomes 0.10 mol/L. Write the units at every step and distinguish changing volume from changing the amount.