What nacl nacl concentration results when 249 ml 249 ml of a 0.850 m 0.850 m nacl nacl solution is mixed with 667 ml 667 ml of a 0.420 m 0.420 m nacl nacl solution?

The answer to your question is 0.54M

Explanation:

Data

Final concentration = ?

Concentration 1 = 0.850 M

Volume 1 = 249 ml = 0.249 l

Concentration 2 = 0.420 M

Volume 2 = 0.667 M

Process

1.- Calculate the number of moles in both solutions

Number of moles 1 = Molarity 1 x Volume 1

                               = 0.850 x 0.249

                               = 0.212

Number of moles 2 = Molarity 2 x Volume 2

                                = 0.420 x 0.667

                                = 0.280

Total number of moles =  0.212 + 0.280

                                      = 0.492

2.-Calculate the final volume

Final volume = Volume 1 + Volume 2

Final volume = 0.249 + 0.667

                      = 0.916 l

3.- Calculate Molarity

Molarity = 0.492 / 0.916

Molarity = 0.54

the formula mass of a molecule or a compound is the sum of the atomic weights of the atoms in its empirical formula

(that's what i know about formula mass)