Molarity and Concentration

Question

A 77.0 mL77.0 mL portion of a 1.30 M1.30 M solution is diluted to a total volume of 258 mL.258 mL. A 129 mL129 mL portion of that solution is diluted by adding 143 mL143 mL of water. What is the final concentration? Assume the volumes are additive.

Answer 1

(77.0 ml)(1.30 M) = (258 ml)(x M) and x = 0.3880 M

(129 ml )(0.3880 M) = (143 ml (x M) and x = 0.350 M