Answer:
The final concentration is 0.45mol/L.
Explanation:
1st) It is necessary to calculate the moles of iron (II) nitrate contained in 35mL of 0.15 mol/L solution:
[tex]\begin{gathered} 1000mL-0.15moles \\ 35mL-x=\frac{35mL*0.15moles}{1000mL} \\ x=0.00525moles \end{gathered}[/tex]In this solution there are 0.00525 moles of iron (II) nitrate.
2nd) Now we have to calculate the moles contained in the 72mL of 0.60 mol/L solution:
[tex]\begin{gathered} 1000mL-0.60moles \\ 72mL-x=\frac{72mL*0.60moles}{1000mL} \\ x=0.0432moles \end{gathered}[/tex]In this solution there are 0.0432 moles of iron (II) nitrate.
3rd) Finally, we have to add both amounts of moles (0.00525 moles + 0.0432moles = 0.04845 moles) considering the total volume (35mL + 72mL = 107mL):
[tex]\begin{gathered} 107mL-0.04845moles \\ 1000mL-x=\frac{1000mL*0.04845moles}{107mL} \\ x=0.45moles \end{gathered}[/tex]So, the final concentration is 0.45mol/L.