Final answer:
To find the final molarity when mixing two Fe(NO3)3 solutions, you add the moles of solute from each solution and divide by the total volume. The final molarity for the mixed solutions is approximately 1.454 M.
Step-by-step explanation:
To calculate the molar concentration of the final solution when a 40 mL volume of 1.80 M Fe(NO3)3 is mixed with 21.5 mL of 0.808 M Fe(NO3)3 solution, we start by finding the total number of moles of Fe(NO3)3 in each solution:
- Moles in 40 mL of 1.80 M solution: (1.80 mol/L) × (0.040 L) = 0.072 mol
- Moles in 21.5 mL of 0.808 M solution: (0.808 mol/L) × (0.0215 L) = 0.017372 mol
Add the moles together to get the total moles of solute:
Total moles of Fe(NO3)3 = 0.072 mol + 0.017372 mol = 0.089372 mol
Then, we find the total volume of the mixed solutions:
Total volume = 40 mL + 21.5 mL = 61.5 mL (which is 0.0615 L)
Now, we can calculate the final concentration using the formula:
Final concentration (M) = Total moles of solute / Total volume of solution
Final concentration = 0.089372 mol / 0.0615 L
Finally, divide the moles by the liters to find the molarity:
Final concentration = 1.454 M (rounded to three significant figures)