A 71.0 mL aliquot of a 1.80 M solution is diluted to a total volume of 218 mL. A 109 mL portion of that solution is diluted by adding 113 mL of water. What is the final concentration? Assume the volumes are additive

The final concentration is 0.288 M (approximately)

Explanation:

Using dilution formula:

C1V1 = C2V2

Where C1 is the initial concentration

C2 is the final concentration

V1 is the initial volume

V2 is the final volume

In the first dilution, C1 = 1.8M,

V1 =71mL, V2 = 218mL from the formula C2 = 1.8 ×71/281

=0.5862M

In the second dilution,

C1 = 0.5862M, V1 = 109mL, V2 = 222 mL (109+113)

C2 = 0.5862 × 109 ÷ 222

= 0.288 M (approximately) assuming volume is additive.