Soil Solution.

Slides:

Advertisements

Similar presentations

General Approach to solving complex equilibria 1)Write all the pertinent reactions 2)Write the charge balance 3)Write the mass balance 4)Write the equilibrium.

Advertisements

Strong Acids/ Bases Strong Acids more readily release H+ into water, they more fully dissociate H2SO4  2 H+ + SO42- Strong Bases more readily release.

Buffer Calculations for Polyprotic Acids A polyprotic acid can form buffer solutions in presence of its conjugate base. For example, phosphoric acid can.

ENVE 201 Environmental Engineering Chemistry 1 Alkalinity Dr. Aslıhan Kerç.

Carbon Dioxide Sources and Sinks: Respiration and Photosynthesis

Dissociation of H 2 O:H 2 O ↔ H + + OH - K w = a H+ a OH- a H2O Under dilute conditions: a i = [i] And a H2O = 1 Hence: K w = [H + ] [OH - ] At 25 o C.

Chemistry 232 Electrolyte Solutions. Thermodynamics of Ions in Solutions  Electrolyte solutions – deviations from ideal behaviour occur at molalities.

Department of Civil & Environmental Engineering

Chapter 10: Effect of Electrolytes on Chemical Equilibria CHE 321: Quantitative Chemical Analysis Dr. Jerome Williams, Ph.D. Saint Leo University.

ACTIVITY. Activity Coefficients No direct way to measure the effect of a single ion in solution (charge balance) Mean Ion Activity Coefficients – determined.

Section 06 General Concepts of Chemical Equilibrium.

Solving Equilibrium problems using the RICE method.

Class evaluations.

ANALYTICAL CHEMISTRY CHEM 3811 CHAPTER 12 DR. AUGUSTINE OFORI AGYEMAN Assistant professor of chemistry Department of natural sciences Clayton state university.

Activity Introduction 1.) Hydration

Ch 12: A Deeper Look at Chemical Equilibrium Up to now we've ignored two points

Carbonate System Alkalinity Lecture 21. TOTH TOTH is the total amount of component H +, rather than the total of the species H +. o Every species containing.

THE RELATIONSHIP BETWEEN H2CO3* AND HCO3-

Lecture 14. Charge balance Sum of positive charges = sum of negative charges In natural waters: [H + ]+2[Ca 2+ ]+2[Mg 2+ ]+[Na + ]+[K + ]=[HCO 3 - ]+2[CO.

Equilibrium Equilibrium Constant, K (or K eq ) describes conditions AT equilibrium CaCO 3(calcite) + H +  Ca 2+ + HCO 3 -

Lecture 6 Activity Scales and Activity Corrections Learn how to make activity corrections Free ion activity coefficients Debye-Huckel Equations Mean Salt.

Acid-Base Equilibria pH and pOH Relationship of Conjugate Pair acid-base strength. When acids or bases control pH:  determine K  predict pH When pH controls.

THE CO 2 -H 2 O SYSTEM - I Carbonic acid is a weak acid of great importance in natural waters. The first step in its formation is the dissolution of CO.

Overview of Some Chemistry in Natural Waters Gases dissolve according to Henry’s law: K H =[X(aq)]/P X ; X=O 2, CO 2, H 2 S, SO 2, etc.  Oxidation-Reduction,

Unit 5: Acids & Bases Lesson 4

Chapter 15. Aqueous Acid-Base Equilibria 15.1 Proton Transfers in Water 15.2 The pH Scale 15.3 Weak Acids and Bases 15.4 Recognizing Acids and Bases 15.5.

Continuation of Acid-Base Chemistry. CALULATE THE pH OF A STRONG ACID Compute the pH and equilibrium concentrations of all species in a 2 x M solution.

PRECIPITATION REACTIONS

1 Example Calculate the volume of 14.8 M NH 3 and the weight of NH 4 Cl (FW = 53.5) you would have to take to prepare 100 mL of a buffer at pH if.

Lectures on respiratory physiology Acid-Base Balance.

Chapter 7 Activity and the Systematic Treatment of Equilibrium

Acids - Ionisation All acids ionise in solution to give ………ions. HCl  H+ H+ H+ H+ + Cl - Cl - (100%) HCl (+ H 2 O) H 2 O)  H 3 O + (aq) H 3 O + (aq)

Determining the Strengths of Acids and Bases

Acids and Bases - the Three Definitions 1.Measurement of pH - the pH meter 2.Bronsted-Lowry definition of acids and bases - an acid is a proton donor -

숙제 : 7 장 문제 : 답이 있는 30 번 까지 짝수 번 문제. Systematic Treatment of Equilibrium In this chapter we will learn: -some of the tools to deal with all types of chemical.

Chapter 16 Precipitation equilibrium Solubility. l All dissolving is an equilibrium. l If there is not much solid it will all dissolve. l As more solid.

Solubility Equilibria (Sec 6-4) K sp = solubility product AgCl(s) = Ag + (aq) + Cl - (aq) K sp = CaF 2 (s) = Ca 2+ (aq) + 2F - (aq) K sp = in general A.

Solubility Equilibria Ksp

Environmental Engineering Course Note 5 (Homogeneous Transformation) Joonhong Park Yonsei CEE Department

Activity Coefficients; Equilibrium Constants Lecture 8.

Learning objective: Using the Brønsted-Lowry theory of acids and bases. Chemistry, 2nd Canadian Edition ©2013 John Wiley & Sons Canada, Ltd.

Class average for Exam I 70. Fe(OH) 3 Fe 3+ (aq) + 3 OH - (aq) [Fe 3+ ][OH - ] 3 = 1.1 x [y][3y] 3 = 1.1 x If there is another source of.

Lecture 20. Equivalence Points Particularly simple relationships occur when the activities of two species are equal. These are determined by equilibrium.

Ely Mine Trip Be here by 8 am! – we should be back by 5pm Sunday at the latest Need: camping gear, warm clothes, clothes that can get messy! Field Notebook.

Solubility Equilibria (Sec 6-4) K sp = solubility product AgCl(s) = Ag + (aq) + Cl - (aq) K sp = CaF 2 (s) = Ca 2+ (aq) + 2F - (aq) K sp = in general A.

Acid-Base Properties of Salt Solutions Salts That Form Neutral Solutions Salts that contain a cation from a strong base AND an anion from a strong acid.

Bjerrum plot showing the activities of inorganic carbon species as a function of pH for a value of total inorganic carbon of mol L -1. In most natural.

Lecture. Acid – Base Equilibria Weak Acid Problem Example: –What is pH and the concentration of major species in a 2.0 x M HCO 2 H (formic acid,

CHEM 1212 Exam 3 Review Presented by UGA’s Academic Resource Center 03/23/16 1.

1.Acid-base review Carbonate system in seawater 2.Carbonate sediments Dissolution / preservation 3.Pore water evidence of respiration-driven dissolution.

1.Acid-base review Carbonate system in seawater 2.Carbonate sediments Dissolution / preservation 3.Pore water evidence of respiration-driven dissolution.

Challenges with simultaneous equilibrium Speciation programs (MINEQL)

Chapter 15: Equilibria in Solution of Weak Acids and Weak Bases Most Weak Acids are Bronsted-Lowry Acids: HC 2 H 3 O 2 + H 2 O  H 3 O + (aq) + C 2 H 3.

Unit III - Acid/Base - Chapter 15

Modeling of geochemical processes Numeric Mathematics Refreshment

Modeling of geochemical processes Equilibrium modeling

Activity of Ions in Solution

Soil solution part 3.

Buffers Complexation.

Predicting the pH of salt solutions

Carbonate System and pH

CH 17: Solubility and Complex-Ion Equilibria

Conjugate Acid - Base Pairs

PH and Concentrations.

9. Systematic Treatment of Equilibrium

Ionic Equilibria: Acids and Bases

part 2: chemical reactions, acids and bases

Chemical Reactions.

Acid-base Dissociation

Solving weak acid equilibrium problems:

Presentation transcript:

Soil Solution

Calculating Activity Coefficients Debye-Hueckel Limiting Equation: log g = - 0.511 Z2 I1/2 for I < 0.01 Extended Debye-Hueckel Equation: for I < 0.1 Davies Equation: for I < 0.5 B is a temperature dependent constant (0.33 @ 25 °C) a is an effective ion size parameter

Ions in Solution: Coordination by Water Molecules

Ions Pairs (Outer-sphere)

Ions Complex (Inner-sphere)

Reaction Driving Force

Hydrolysis Reactions Fe3+ • 6H2O Fe(OH)2+ • 5H2O

Hydrolysis Reactions Fe3+ + H2O <--> Fe(OH)2+ + H+ K = 10-2.19 Fe(OH)2+ + H2O <--> Fe(OH)2+ + H+ K = 10-3.5 Fe(OH)2+ + H2O <--> Fe(OH)3o + H+ K = 10-7.4 Fe(OH)3o + H2O <--> Fe(OH)4- + H+ K = 10-8.5

Hydrolysis Reactions: Anionic log K H3PO4o  H+ + H2PO4- -2.15 H2PO4-  H+ + HPO42- -7.20 HPO42-  H+ + PO43- -12.35

Complex Equilibria

Carbonate Species/Reactions H2O CO2 (g)  CO2(aq) H2CO3  CO2(aq) + H2O H2CO3  H+ + HCO3- HCO3-  H+ + CO32- CaCO3 (s)  Ca2+ + CO32-

CO2 Hydration H2O CO2 (g)  CO2(aq) CO2(aq) = KH PCO2 KH = Henry's Law Constant = 0.033 M (at 25 °C)

Dissociation Reactions Log K H2CO3  H+ + HCO3- -6.36 HCO3-  H+ + CO32- -10.33 CaCO3 (s)  Ca2+ + CO32- -8.35

Equilibrium Equations Log K H2CO3  H+ + HCO3- -6.36 HCO3-  H+ + CO32- -10.33 H2O  H+ + OH- -14 CaCO3 (s)  Ca2+ + CO32- -8.35 CO2(aq) = KH PCO2

Mass and Charge Balance [C]T = [H2CO3*] + [HCO3-] + [CO32-] + [CaCO3] [H+] + 2[Ca2+] = [OH-] + [HCO3-] + 2[CO32-] charge

Species Distribution H2CO3 HCO3- CO32-

Simplifying Assumptions (!) 1. At pH < 9, [CO32-] << [HCO3-], [H2CO3*] 2. At PCO2 > 10-3.5 atm, [HCO3-] >> [OH-] [HCO3-], pH 7 = 1.44 mM mass [C]T = [H2CO3*] + [HCO3-] + [CaCO3] [H+] + 2[Ca2+] = [HCO3-] charge