If 3.5 mL of distilled water is added to 1.5mL of a 0.150 M solution of CoCl2, what is the concentration of the resulting solution?

M1V1=M2V2

M1= 0.150
V1= 1.5mL
M2= 3.5?

I suppose we are to assume that the volumes are additive.

M1V1 = M2V2
0.150*1.5 = M2*(3.5+1.5)
M2 = 0.045M

Another way.
You start with 1.5 mL and end up with 5.0 mL (if the solutions are additive) so 0.150M x (1.5/5.0) = 0.045M

To find the concentration of the resulting solution, we can use the formula M1V1 = M2V2, where M1 is the initial concentration, V1 is the initial volume, M2 is the final concentration, and V2 is the final volume.

In this case, M1 = 0.150 M (the initial concentration of the CoCl2 solution) and V1 = 1.5 mL (the initial volume).

To find the final volume, we need to take into account that 3.5 mL of distilled water is added to the initial solution. Therefore, the final volume (V2) will be the sum of the initial volume and the volume of water added, which is 1.5 mL + 3.5 mL = 5.0 mL.

Now, we can rearrange the formula to solve for M2:

M2 = (M1 * V1) / V2

Substituting the values we have:

M2 = (0.150 M * 1.5 mL) / 5.0 mL

Multiply 0.150 M by 1.5 mL:

M2 = 0.225 / 5.0 mL

Divide 0.225 by 5.0 mL:

M2 = 0.045 M

Therefore, the concentration of the resulting solution is 0.045 M.