/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none}

91影视

Ion pairing. As in Problem 8-30, find the concentration, ionic strength, and ion pair fraction in localid="1654942556135" 0.025FNa2SO4. Assume that the size of theNaSO-4=500pm

Short Answer

Expert verified

Thus the Ionic Strength and Ion Pair Fraction of 0.025FNa2SO4 is 0.07051M and 9%

Step by step solution

01

Step 1:Calculating the Ionic Strength and Ion Pair Fraction.

This is also a task that need to be performed in the Excel. And the values will be,

Na+=0.04775MSO2-4=0.02275MNaSO-4=0.002246M

Ionic Strength =0.070514M

Ion Pair Fraction =9%

02

Step 2:Ionic Strength and Ion Pair Fraction of 0.025  F   Na2SO4

Thus the Ionic Strength and Ion Pair Fraction of 0.025FNa2SO4 is 0.07051M and 9%

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Write two mass balances for a 1.0Lsolution containing 0.100molof sodium acetate.

Systematic treatment of equilibrium for ion pairing. Let鈥檚 derive the fraction of ion pairing for the salt in Box 8-1, which are 0.025FNaCI,Na2SO4,MgCI2,MgSO4. Each case is somewhat different. All of the solutions will be near neutral pH because hydrolysis reactions of Mg2+,SO2-4,Na+,CI-have small equilibrium constants. Therefore, we assume that H+=OH-and omit these species from the calculations. We work MgCI2as an example and then you asked to work each of the others. The ion-pair equilibrium constant, Kipcomes from Appendix J.

Pertinent reaction:

Mg2+CI-MgCI+aqKip=MgCI+aqMgCI+Mg2+Mg2+CI-CI-logKip=0.6.pKip=-0.6A

Charge balance (omitting H+,OH-whose concentrations are both small in comparison with Mg+,MgCI+,CI-:

role="math" localid="1655088043259" 2Mg2-+MgCI+=CI-B

Mass balance:

Mg2-+MgCI+=F=0.025MCCI-+MgCI+=2F=0.050MD

Only two of the three equations (B),(C) and (D) are independent. If you double (c) and subtract (D) , you will produce (B). we choose (C) and (D) as independent equations.

Equilibrium constant expression : Equation (A)

Count : 3 equations (A,C,D) and 3 unknowns Mg2+,MgCI+,CI-

Solve: We will use Solver to find

numberofunknowns-numberofequiliberia=3-1=2unknown concentrations.

The spreadsheet shows the work. Formal concentration F=0.0025Mappears in cell G2. We estimate pMg2+,pCI-in cell B8and B9. The ionic strength in cell B5is given by the formula in cell H24. Excel must be set to allow for circular definitions as described on page role="math" localid="1655088766279" 179. The sizes of role="math" localid="1655088853561" Mg2+,CI-are from Table 8-1and the size of MgCI+is a guess. Activity coefficient are computed in columns E,F. Mass balance b1=F-Mg2+-MGCI+,b2=2F-CI--MgCI+appears in cell H14,H15, and the sum of squares b21+b22 appears in cell H16. The charge balance is not used because it is not independentof the two mass balances.

Solver is invoked to minimizes b21+b22in cell H16be varying pMg2+,pCI-in cells B8and B9. From the optimized concentration, the ion-pair fraction =MgCI+F=0.0815is computed in cell D15.

The problem: Create a spreadsheet like the one for MgCI+to find the concentration, ionic strength, and ion pair fraction in 0.025MNaCI. The ion pair formation constant from Appendix J is log Kip=10-0.5for the reaction Na++CI-NaCIaq. The two mass balances are Na++NaCIaq=F,Na+=CI-Estimate pNa+,pCI- for input and then minimizes the sum of square of the two mass balances.

State the meaning of the charge and mass balance equations.

Ammonia equilibrium solved with Goal Seek. Modify Figure 8-7to find the concentration of species in 0.05MNH3. The only change required is the value of F . How do the pH and fraction of ammonia hydrolysis role="math" localid="1654938461639" (=[NH+4][NH+4]+[NH3])change when the formal concentration of NH3 increases from 0.01 to 0.05 M?

Solubility with Activity: Find the concentration of the major species in a saturated aqueous solution of LiF. Consider these reactions:

LiFsLi++F-Ksp=Li+Li+F-F-LiFsLiFaqKionpair=LiFaq纬尝颈贵aqF-+H2OHF+OH-Kb=KwKaforHFH2OKwH++OH-Kw=H+H+OH-OH-

  1. Look up the equilibrium constants in the appendixes and write their pK values. The ion pair reaction is the sum of localid="1654945209684" LiFsLi++F-from the Appendix FandLi+LiFaqfrom Appendix J. write the equilibrium constant expressions and the charge and mass balance.
  2. Create a spreadsheet that uses activities to find the concentration of all species and the ionic strength. Use pH and pOH as independent variables to estimate. It does not work to choose pH and pLi because their concentration fixes that of the other through the relation Ksp=Li+Li+F-F-
See all solutions

Recommended explanations on Chemistry Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.