4.00 mL of a 1.50E-3 M solution of crystal violet is mixed with 8.00 mL of water. What is the concentration of the resulting solution (in units of M)?

Answer 1

First, the definition of Molarity (M) is given as:

M = n (moles of solute) / V (volume of solution in liters)

Before adding the water to the solution, we have a molarity of 0.00150 M and solution volume of 4.00 mL. We can use this information to solve for the number of moles of crystal violet in the solution by multiplying both sides of the equation by V.

n = MV = (0.00150 M)(0.00400 L) = 6.00 E-6 moles crystal violet

Now that we have this value for n, we can solve for the molarity of the new solution (remember that the total number of moles of crystal violet will not change after the water is added). Plugging this value into the molarity equation along with the new solution volume (12.00 mL), we obtain:

M = n/V = (6.00 E-6 moles crystal violet) / (0.012 L) = 5E-4 M