Figure 3-3 Dilution of a solution. (a) A 100.-mL volumetric flask is filled to the
calibration line with a 0.100 Mpotassium chromate, K 2 CrO 4 solution. (b) The 0.100 M
K 2 CrO 4 solution is transferred into a 1.00-L volumetric flask. The smaller flask is rinsed
with a small amount of distilled H 2 O. The rinse solution is added to the solution in the
larger flask. To make sure that all the original K 2 CrO 4 solution is transferred to the larger
flask, the smaller flask is rinsed twice more and each rinse is added to the solution in the
larger flask. (c) Distilled water is added to the 1.00-L flask until the liquid level coincides
with its calibration line. The flask is stoppered and its contents are mixed thoroughly. The
new solution is 0.0100 MK 2 CrO 4. (100. mL of 0.100 MK 2 CrO 4 solution has been diluted
to 1000. mL.) The 100. mL of original solution and the 1000. mL of final solution both
contain the amount of K 2 CrO 4 dissolved in the original 100. mL of 0.100 MK 2 CrO 4.
3-7 Dilution of Solutions 109The dilute solution contains 1.00 L0.900 M0.900 mol of H 2 SO 4 , so 0.900 mol of H 2 SO 4
must also be present in the original concentrated solution. Indeed, 0.0500 L18.0 M0.900
mol of H 2 SO 4.
You should now work Exercises 70 and 72.
(a)(c)K+ =CrO2– 4 =(b)