A buret (initial and final buret reading were 2.20 mL and 11.86 mL) was used to deliver a sample of 2.1E-5 M stock dye into a 25.0 mL volumetric flask. The dye was then diluted with water to exactly 25.0 mL. Calculate the molarity of the resulting solution.
You delivered from the buret exactly 11.86-2.20 = ?? mL of the dye.
Final concn then = 2.1E-5 x (??mL/25.0 mL) = xx M
To calculate the molarity of the resulting solution, we need to determine the number of moles of the dye in the 25.0 mL volumetric flask.
First, let's calculate the volume of dye added to the flask using the buret readings. The initial buret reading is 2.20 mL, and the final buret reading is 11.86 mL. The difference between these readings will give us the volume of dye added to the volumetric flask:
Volume of dye added = Final buret reading - Initial buret reading
= 11.86 mL - 2.20 mL
= 9.66 mL
Next, we need to convert this volume into liters:
Volume of dye added in liters = 9.66 mL * (1 L / 1000 mL)
= 0.00966 L
Now, we can calculate the moles of dye in the solution using the molarity and volume of dye added:
Moles of dye = Molarity * Volume (in liters)
= 2.1E-5 M * 0.00966 L
= 2.028E-7 moles
Since the dye was then diluted with water to exactly 25.0 mL, the resulting solution contains 2.028E-7 moles of dye in 25.0 mL of solution.
Finally, we can calculate the molarity of the resulting solution:
Molarity of resulting solution = Moles of dye / Volume of solution (in liters)
= 2.028E-7 moles / 0.025 L
= 8.11E-6 M
Therefore, the molarity of the resulting solution is 8.11E-6 M.