Final answer:
The final concentration of nitrate ions after combining both potassium nitrate and calcium nitrate solutions is calculated to be 2.325 M.
Step-by-step explanation:
To determine the resulting nitrate ion concentration when combining solutions of potassium nitrate and calcium nitrate, you need to calculate the total number of moles of nitrate ions in the mixed solution and then divide by the final volume. Potassium nitrate, KNO₃, and calcium nitrate, Ca(NO₃)₂, both dissociate to give nitrate ions, NO₃⁻
The number of moles of nitrate from potassium nitrate is:
- 95.0 mL × (1 L / 1000 mL) × 0.992 mol/L KNO₃
= 0.09424 moles of NO₃⁻
For calcium nitrate:
- 155.5 mL × (1 L / 1000 mL) × 1.570 mol/L Ca(NO3)2 = 0.244135 moles of Ca(NO₃)₂
- Since each mole of Ca(NO₃)₂ gives 2 moles of NO₃⁻ , total moles of NO₃⁻ from Ca(NO₃)₂ = 0.244135 × 2 = 0.48827 moles.
Total moles of NO₃⁻ in the combined solution = 0.09424 + 0.48827 = 0.58251 moles.
The total volume of the solution is 95.0 mL + 155.5 mL = 250.5 mL or 0.2505 L.
The final concentration of NO₃⁻ is:
0.58251 moles / 0.2505 L = 2.325 M (rounded to three significant figures).