Calculate the concentration of each ion in the following solutions obtained by mixing: (a) \(32.0 \mathrm{~mL}\) of \(0.30 \mathrm{M} \mathrm{KMnO}_{4}\) (b) \(60.0 \mathrm{~mL}\) of \(0.100 \mathrm{M} \mathrm{ZnCl}_{2}^{+}\) with \(15.0 \mathrm{~mL}\) of \(0.60 \mathrm{MKMnO}_{4}\) with \(5.0 \mathrm{~mL}\) of $0.200 \mathrm{M} \mathrm{Zn}\left(\mathrm{NO}_{3}\right)_{2},(\mathbf{c}) 4.2 \mathrm{~g}$ of \(\mathrm{CaCl}_{2}\) in \(150.0 \mathrm{~mL}\) of \(0.02 M \mathrm{KCl}\) solution. Assume that the volumes are additive.

Short Answer

Expert verified
In the given solutions, the final concentrations are: (a) K+ = \(0.396 \ \mathrm{M}\), MnO4- = \(0.396 \ \mathrm{M}\) (b) Zn2+ = \(0.108 \ \mathrm{M}\), Cl- = \(0.185 \ \mathrm{M}\), NO3- = \(0.031 \ \mathrm{M}\) (c) Ca2+ = \(0.239 \ \mathrm{M}\), K+ = \(0.019 \ \mathrm{M}\), Cl- = \(0.496 \ \mathrm{M}\)

Step by step solution

01

(a) Calculate moles of each ion in the solution of KMnO4

First, we need to determine the moles of each ion in the \(32.0 \mathrm{mL}\) of \(0.30 \mathrm{M} \ \mathrm{KMnO}_{4}\) solution. Since molarity (M) = moles of solute/volume of solution in L, we can calculate the moles of KMnO4. Moles of KMnO4 = Molarity × Volume = \(0.30 \mathrm{M} \times 32.0 \mathrm{mL}\) However, we need to convert the volume from mL to L. Moles of KMnO4 = \(0.30 \mathrm{M} \times 0.032 \mathrm{L} = 0.0096 \ \mathrm{mol}\) Now we will find the moles of ions in the solution. KMnO4 dissociates into K+ and MnO4- ions. Moles of K+ = moles of KMnO4 = \(0.0096 \ \mathrm{mol}\) Moles of MnO4- = moles of KMnO4 = \(0.0096 \ \mathrm{mol}\)
02

(a) Calculate moles of each ion in the mixture

Now, let's find the moles of each ion in the mixture of solutions. Moles of K+ in the mixture = Moles of K+ in 32.0 mL of 0.30 M KMnO4 + moles of K+ in 15.0 mL of 0.60 M KMnO4 Moles of K+ in the mixture = \(0.0096 \mathrm{mol} + 0.60 \mathrm{M} \times 0.015 \mathrm{L}\) Moles of K+ in the mixture = \(0.0096 \mathrm{mol} + 0.0090 \mathrm{mol} = 0.0186 \mathrm{mol}\) Moles of MnO4- in the mixture = Moles of MnO4- in 32.0 mL of 0.30 M KMnO4 + moles of MnO4- in 15.0 mL of 0.60 M KMnO4 Moles of MnO4- in the mixture = \(0.0096 \mathrm{mol} + 0.60 \mathrm{M} \times 0.015 \mathrm{L}\) Moles of MnO4- in the mixture = \(0.0096 \mathrm{mol} + 0.0090 \mathrm{mol} = 0.0186 \mathrm{mol}\)
03

(a) Calculate the concentration of each ion

Now that we have the moles of each ion in the mixture, we can find their final concentrations. The total volume of the mixture is \(32.0 \mathrm{mL} + 15.0 \mathrm{mL} = 47.0 \mathrm{mL}\). Concentration of K+ = Moles of K+ in the mixture / Total volume of the mixture = \(0.0186 \ \mathrm{mol} / 0.047 \ \mathrm{L} = 0.396 \ \mathrm{M}\) Concentration of MnO4- = Moles of MnO4- in the mixture / Total volume of the mixture = \(0.0186 \ \mathrm{mol} / 0.047 \ \mathrm{L} = 0.396 \ \mathrm{M}\) The final concentrations in the mixture are: K+ = \(0.396 \ \mathrm{M}\) MnO4- = \(0.396 \ \mathrm{M}\)
04

(b) Mixing ZnCl2 and Zn(NO3)2 solutions

For part (b), we have to mix \(60.0 \mathrm{mL}\) of \(0.100 \mathrm{M} \ \mathrm{ZnCl}_{2}^{+}\) solution and \(5.0 \mathrm{mL}\) of \(0.200 \mathrm{M} \ \mathrm{Zn}\left(\mathrm{NO}_{3}\right)_{2}\) solution. For both solutions, we have multiple ions to consider. First, we need to calculate the moles of each ion in both solutions. For ZnCl2: Moles of Zn2+ = Molarity × Volume = \(0.100 \mathrm{M} \times 0.060 \mathrm{L} = 0.0060 \ \mathrm{mol}\) Moles of Cl- = 2 × Moles of Zn2+ (since there are two Cl- ions in ZnCl2) = 2 × \(0.0060 \ \mathrm{mol} = 0.0120 \ \mathrm{mol}\) For Zn(NO3)2: Moles of Zn2+ = Molarity × Volume = \(0.200 \mathrm{M} \times 0.005 \mathrm{L} = 0.0010 \ \mathrm{mol}\) Moles of NO3- = 2 × Moles of Zn2+ (since there are two NO3- ions in Zn(NO3)2) = 2 × \(0.0010 \ \mathrm{mol} = 0.0020 \ \mathrm{mol}\) Now we sum up the moles of each ion in the mixture: Moles of Zn2+ in the mixture = Moles of Zn2+ in ZnCl2 + Moles of Zn2+ in Zn(NO3)2 = \(0.0060 \mathrm{mol} + 0.0010 \mathrm{mol} = 0.0070 \mathrm{mol}\) Moles of Cl- in the mixture = Moles of Cl- in ZnCl2 = \(0.0120 \ \mathrm{mol}\) Moles of NO3- in the mixture = Moles of NO3- in Zn(NO3)2 = \(0.0020 \ \mathrm{mol}\) Now we calculate the concentration of each ion in the mixture. The total volume of the mixture is \(60.0 \mathrm{mL} + 5.0 \mathrm{mL} = 65.0 \mathrm{mL}\). Concentration of Zn2+ = Moles of Zn2+ in the mixture / Total volume of the mixture = \(0.0070 \ \mathrm{mol} / 0.065 \ \mathrm{L} = 0.108 \ \mathrm{M}\) Concentration of Cl- = Moles of Cl- in the mixture / Total volume of the mixture = \(0.0120 \ \mathrm{mol} / 0.065 \ \mathrm{L} = 0.185 \ \mathrm{M}\) Concentration of NO3- = Moles of NO3- in the mixture / Total volume of the mixture = \(0.0020 \ \mathrm{mol} / 0.065 \ \mathrm{L} = 0.031 \ \mathrm{M}\) The final concentrations in the mixture are: Zn2+ = \(0.108 \ \mathrm{M}\) Cl- = \(0.185 \ \mathrm{M}\) NO3- = \(0.031 \ \mathrm{M}\)
05

(c) Mixing CaCl2 and KCl solutions

For part (c), we have to mix \(4.2 \mathrm{g}\) of \(\mathrm{CaCl}_{2}\) and \(150.0 \mathrm{mL}\) of \(0.02 \mathrm{M} \ \mathrm{KCl}\). First, let's find the moles of CaCl2: Moles of CaCl2 = mass / molar mass = \(4.2 \mathrm{g} / 110.98 \mathrm{g/mol} = 0.0378 \ \mathrm{mol}\) Now we find the moles of ions in the CaCl2: Moles of Ca2+ = moles of CaCl2 = \(0.0378 \ \mathrm{mol}\) Moles of Cl- in CaCl2 = 2 × moles of Ca2+ (since there are two Cl- ions in CaCl2) = 2 × \(0.0378 \ \mathrm{mol} = 0.0756 \mathrm{mol}\) Next, let's find the moles of ions in the KCl solution: Moles of K+ = Molarity × Volume = \(0.02 \mathrm{M} \times 0.150 \mathrm{L} = 0.0030 \ \mathrm{mol}\) Moles of Cl- in KCl solution = Moles of K+ (since there is one Cl- ion in KCl) = \(0.0030 \ \mathrm{mol}\) Now we sum up the moles of each ion in the mixture: Moles of Ca2+ in the mixture = Moles of Ca2+ = \(0.0378 \ \mathrm{mol}\) Moles of K+ in the mixture = Moles of K+ = \(0.0030 \ \mathrm{mol}\) Moles of Cl- in the mixture = Moles of Cl- in CaCl2 + Moles of Cl- in KCl = \(0.0756 \ \mathrm{mol} + 0.0030 \ \mathrm{mol} = 0.0786 \ \mathrm{mol}\) Now, calculate the concentration of each ion in the mixture. The total volume of the mixture is \(4.2 \mathrm{g} \times 2 \mathrm{mL/g} + 150.0 \mathrm{mL} = 158.4 \mathrm{mL}\). Concentration of Ca2+ = Moles of Ca2+ in the mixture / Total volume of the mixture = \(0.0378 \ \mathrm{mol} / 0.1584 \ \mathrm{L} = 0.239 \ \mathrm{M}\) Concentration of K+ = Moles of K+ in the mixture / Total volume of the mixture = \(0.0030 \ \mathrm{mol} / 0.1584 \ \mathrm{L} = 0.019 \ \mathrm{M}\) Concentration of Cl- = Moles of Cl- in the mixture / Total volume of the mixture = \(0.0786 \ \mathrm{mol} / 0.1584 \ \mathrm{L} = 0.496 \ \mathrm{M}\) The final concentrations in the mixture are: Ca2+ = \(0.239 \ \mathrm{M}\) K+ = \(0.019 \ \mathrm{M}\) Cl- = \(0.496 \ \mathrm{M}\)

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