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Chapter 11: Solutions: Properties and Behavior
Chapter 11: Solutions: Properties and Behavior Learning Objectives 11.1: Interactions between Ions • Be able to estimate changes in lattice energy from the potential energy form of Coulomb’s Law, Q Q Cation Anion , in which is lattice energy, is a proportionality constant, is the charge on E = k E k QCation r the cation, Q is the charge on the anion, and r is the distance between the centers of the ions. Anion 11.2: Energy Changes during Formation and Dissolution of Ionic Compounds • Understand the concept of lattice energy and how it is a quantitative measure of stability for any ionic solid. As lattice energy increases, the stability of the ionic solid increases. • Be able to estimate changes in lattice energy from the potential energy form of Coulomb’s Law, Q Q Cation Anion , in which is lattice energy, is a proportionality constant, is the charge on E = k E k QCation r the cation, Q is the charge on the anion, and r is the distance between the centers of the ions. Anion • Be able to determine lattice energies using a Born-Haber cycle, which is a Hess’s Law process using ionization energies, electron affinities, and enthalpies for other atomic and molecular properties. • Be able to describe a molecular view of the solution process using Hess’s Law: 1. Solvent → Solvent Particles where ∆Hsolvent separation is endothermic. 2. Solute → Solute Particles where ∆Hsolute separation is endothermic. 3. Solvent Particles + Solute Particles → Solution where ∆Hsolvation can be endo- or exothermic. 4. ∆Hsolution = ∆Hsolvent separation + ∆Hsolute separation + ∆Hsolvation This is a Hess’s Law thinking process, and ∆Hsolvation is called the ∆Hhydration when the solvent is water. -
Assembly of Multi-Flavored Two-Dimensional Colloidal Crystals† Cite This: Soft Matter, 2017, 13,5397 Nathan A
Soft Matter View Article Online PAPER View Journal | View Issue Assembly of multi-flavored two-dimensional colloidal crystals† Cite this: Soft Matter, 2017, 13,5397 Nathan A. Mahynski, *a Hasan Zerze,b Harold W. Hatch, a Vincent K. Shena and Jeetain Mittal *b We systematically investigate the assembly of binary multi-flavored colloidal mixtures in two dimensions. In these mixtures all pairwise interactions between species may be tuned independently. This introduces an additional degree of freedom over more traditional binary mixtures with fixed mixing rules, which is anticipated to open new avenues for directed self-assembly. At present, colloidal self-assembly into non-trivial lattices tends to require either high pressures for isotropically interacting particles, or the introduction of directionally anisotropic interactions. Here we demonstrate tunable assembly into a plethora of structures which requires neither of these conditions. We develop a minimal model that defines a three-dimensional phase space containing one dimension for each pairwise interaction, then employ various computational techniques to map out regions of this phase space in which the system self-assembles into these different morphologies. We then present a mean-field model that is capable of reproducing these results for size-symmetric mixtures, which reveals how to target different structures by tuning pairwise interactions, solution stoichiometry, or both. Concerning particle size asymmetry, we find Received 19th May 2017, that domains in this model’s phase space, corresponding to different morphologies, tend to undergo a Accepted 30th June 2017 continuous ‘‘rotation’’ whose magnitude is proportional to the size asymmetry. Such continuity enables DOI: 10.1039/c7sm01005b one to estimate the relative stability of different lattices for arbitrary size asymmetries. -
CHAPTER 20: Lattice Energy
CHAPTER 20: Lattice Energy 20.1 Introduction to Lattice Energy 20.2 Born-Haber Cycles 20.3 Ion Polarisation 20.4 Enthalpy Changes in Solutions Learning outcomes: (a) explain and use the term lattice energy (∆H negative, i.e. gaseous ions to solid lattice). (b) explain, in qualitative terms, the effect of ionic charge and of ionic radius on the numerical magnitude of a lattice energy. (c) apply Hess’ Law to construct simple energy cycles, and carry out calculations involving such cycles and relevant energy terms, with particular reference to: (i) the formation of a simple ionic solid and of its aqueous solution. (ii) Born-Haber cycles (including ionisation energy and electron affinity). (d) interpret and explain qualitatively the trend in the thermal stability of the nitrates and carbonates in terms of the charge density of the cation and the polarisability of the large anion. (e) interpret and explain qualitatively the variation in solubility of Group II sulfates in terms of relative magnitudes of the enthalpy change of hydration and the corresponding lattice energy. 20.1 Introduction to Lattice Energy What is lattice energy? 1) In a solid ionic crystal lattice, the ions are bonded by strong ionic bonds between them. These forces are only completely broken when the ions are in gaseous state. 2) Lattice energy(or lattice enthalpy) is the enthalpy change when one mole of solid ionic lattice is formed from its scattered gaseous ions. 3) Lattice energy is always negative. This is because energy is always released when bonds are formed. 4) Use sodium chloride, NaCl as an example. -
Calculating Lattice Energies Using the Born-Haber Cycle an Extension Activity for AP Chemistry Students
Calculating Lattice Energies Using the Born-Haber Cycle An Extension Activity for AP Chemistry Students A particular set of equations known as a Born-Haber cycle demonstrates how chemists are able to use the first law of thermodynamics—that the energy of the universe is conserved in any chemical or physical change—to find an unknown energy value that is difficult or impossible to measure experimentally. Some energy quantities, such as the lattice energy of a mineral or the electron affinity of an atom, can be difficult to measure in the lab. Examining a Born-Haber cycle we see that there is more than one path to the formation of a substance in a particular state, and that if we use consistent definitions, an energy value that we seek can be calculated from energy values that we already know. The following exercise will help us see the way these energy values relate to one another, give us practice with their definitions and symbols, and deepen our insight to their meaning when we see them in other types of problems. Each physical or chemical change represented has: • an equation that represents a clearly defined physical or chemical change; • a definition of the particular type of energy change; • a symbol or abbreviation for the energy change equal to a value for the change in enthalpy (ΔH), the energy that is released or absorbed during the change, expressed in kJ/mol; and • a name by which that change in enthalpy is commonly known. To set up the equations in a Born-Haber cycle, cut out the cards for names, equations, defini- tions, and symbols with energy values. -
Instruction Sheet 667 4961
06/05-W97-Se Instruction sheet 667 4961 7 1 2 Apparatus for molar mass determination, boiling point method (667 4961) 3 6 5 4 1 Thermometer connection 2 Drying tube 3 Internal condenser 4 Boiling tube with 2 side tubes 5 Boiling jacket 6 Filler neck 7 Glass stopper 1 Description 2 Scope of supply The apparatus for determining the molar mass, boiling point 1 boiling tube with 2 side tubes method (ebullioscopic method) allows the molar mass of a 1 internal condensor with ST 19/26 dissolved substance to be determined from the amount by which the boiling point of the pure solvent is increased. For an 1 drying tube with ST 7/16 exact measurement of the boiling-point elevation to an 1 glass stopper ST 14.5/23 accuracy of ±0.01 K, the Beckmann thermometer (666 173) or 1 boiling jacket a digital thermometer (666 209 or 666 454 respectively) with an NTC temperature sensor is used. 3 Technical data Thermometer connection: ST 19/26 Drying tube: ST 7/16 Internal condensor: ST 19/26 Filler neck: ST 14.5/23 Boiling jacket: Glass cylinder with insulation (asbestos free) Safety notes 4 Accessories In order to avoid delays in boiling: 1 Beckmann thermometer 666 173 - Put glass beads, Raschig rings or a platinum tetrahe- or dron into the boiling tube. 1 digital thermometer 666 209 If readily flammable solvents are used: or 666 454 - Remove all naked flames when filling and opening the 1 temperature sensor, NTC, 260 mm 666 2121 apparatus. 1 reducing adapter ST 19/26 to GL18 665 305 1 gas or electric burner Instruction sheet 667 4961 Page 2/3 5 Putting the apparatus into operation 6 Carrying out the experiment - Accurately measure off approx. -
Solubility and Precipitates
Solubility and Precipitates • Everything dissolves in everything else, but to what extent? • Rule of thumb: If solubility limit < 0.01 M, it is considered insoluble Solubility rules (guidelines) - - - + + + + + + • All NO3 , C2H3O2 , ClO4 , Group IA metal ions (Li , Na , K , Rb , Cs ) and NH4 salts are soluble. • Most Cl-, Br-, and I- salts are soluble. 2+ + 2+ – Exceptions: Pb , Ag , and Hg2 2- • Most SO4 salts are soluble. 2+ 2+ 2+ 2+ 2+ – Exceptions: Sr , Ba , Pb and Hg2 (Ca is slightly soluble) 2- - 3- 2- • Most CO3 , OH , PO4 , and S salts are insoluble. – Exceptions: Group IA metal ions (Ca2+, Ba2+ and Sr2+ are slightly soluble) If you’re not part of the solution… • You’re part of the precipitate! • In net ionic equations, the precipitate does not dissociate (stays as one entity) • Example: AgNO3 + NaCl à AgCl + NaNO3 (overall) + - + - + - • Ag + NO3 + Na + Cl à AgCl + Na + NO3 (ionic) • Ag+ + Cl- à AgCl (net ionic) Empirical Gas Laws • Early experiments conducted to understand the relationship between P, V and T (and number of moles n) • Results were based purely on observation – No theoretical understanding of what was taking place • Systematic variation of one variable while measuring another, keeping the remaining variables fixed Boyle’s Law (1662) • For a closed system (i.e. no gas can enter or leave) undergoing an isothermal process (constant T), there is an inverse relationship between the pressure and volume of a gas (regardless of the identity of the gas) V α 1/P • To turn this into an equality, introduce a constant of proportionality (a) à V = a/P, or PV = a • Since the product of PV is equal to a constant, it must UNIVERSALLY (for all values of P and V) be equal to the same constant P1V1 = P2V2 Boyle’s Law • There is an inverse relationship between P and V (isothermal, closed system) https://en.wikipedia.org/wiki/Boyle%27s_law Charles’ Law (1787) • For a closed system undergoing an isobaric process (constant P), there is a direct relationship between the volume and temperature of a gas. -
A.P. Chemistry Quiz: Ch. 8, Bonding Lattice Energy, Bond Enthalpy, Electronegativity, and Polarity Name___
A.P. Chemistry Quiz: Ch. 8, Bonding Lattice Energy, Bond Enthalpy, Electronegativity, and Polarity Name___________________________________ MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. The diagram below is the Born-Haber cycle for the formation of crystalline potassium fluoride. 1) Which energy change corresponds to the negative lattice energy of potassium fluoride? A) 5 B) 1 C) 6 D) 4 E) 2 2) Which energy change corresponds to the electron affinity of fluorine? A) 2 B) 5 C) 6 D) 4 E) 1 3) Which energy change corresponds to the first ionization energy of potassium? A) 2 B) 4 C) 3 D) 5 E) 6 4) Given the electronegativities below, which covalent single bond is most polar? Element: H C N O Electronegativity: 2.1 2.5 3.0 3.5 A) C-H B) O-C C) O-H D) N-H E) O-N 5) Of the molecules below, the bond in __________ is the most polar. A) HBr B) HCl C) HF D) HI E) H2 A-1 6) Using the table of average bond energies below, the DH for the reaction is __________ kJ. Bond: C”C C-C H-I C-I C-H D (kJ/mol): 839 348 299 240 413 A) +160 B) -63 C) +63 D) -160 E) -217 7) Of the bonds C-N, ChN, and C”N, the C-N bond is __________. A) strongest/longest B) weakest/longest C) intermediate in both strength and length D) strongest/shortest E) weakest/shortest A-2 Answer Key Testname: QUIZ_BONDING_CH_08.TST MULTIPLE CHOICE. -
Department of Chemistry, Question Bank B
Shri R. L. T. College of Science, Akola Department of Chemistry, Question Bank B. Sc-II (Semester-IV) Paper: 4S Chemistry Physical Chemistry (Unit-V & VI) Short Answer Question (1 Mark) 1.What is the molal elevation constant? Give its unit. 2.What is ebullioscopic constant? 3.What is cryoscopic constant? 4.What is Van’t Hoff Factor? 5.What is colligative property? Name the four colligative properties? 6.What is elevation of boiling point? 7.What is depression of freezing point? 8.What is Axis of Symmetry? 9.What is Low of Symmetry? 10. What is unit Cell? 11. Define the Following terms (1 M each) 12. i) Unit cell ii) Space lattice iii) Plane of Symmetry iv) Point of symmetry v) Weiss indices vi) Center of symmetry vii) Lattice point viii) Axis of symmetry ix) Simple cubic crystal x) Body centered cubic xi) Face centered cubic 13. Define the Following terms (1 M each) i) Dilute solution ii) Boiling Point, iii) Freezing Point, iv) Van’t Hoff Factor, v) Molal Elevation constant, vi) Molal depression constant vii) Solution viii) Solvent Fill in the Blanks (1/2 Mark Each) i) Phenol in chloroform to form double molecule. ii) The elevation in boiling point is proportional to pressure. iii) Van’t Hoff factor for sucrose is . iv) The property which depends on the number of particals of the substance in solution is known as property. v) The presence of solute the boiling point of solvent. vi) The presence of solute the freezing point of solvent vii) What is Beckmann thermometer is a thermometer. -
Solutions Thermodynamics Dcians
Solutions Thermodynamics DCI Name _____________________________ Section ______ 1. The three attractive interactions which are important in solution formation are; solute-solute interactions, solvent-solvent interactions, and solute-solvent interactions. Define each of these interactions and describe their importance in determining whether a particular solute-solvent pair will form a homogeneous mixture or a heterogeneous mixture. Solute-solute interactions are the intermolecular attractions between solute particles. Solvent-solvent interactions are the intermolecular attractions between solvent particles. Solute-solvent interactions are the intermolecular attractions between a solute particle and a solvent particle. If the intermolecular attractions between solute particles are different compared to the intermolecular attractions between solvent particles it is unlikely dissolution will occur. Similar intermolecular attractions between solute particles and between solvent particles make it more likely a solution will form when the two are mixed. Shown below are two beakers. One contains liquid The two liquids form a water and the other contains liquid carbon heterogeneous mixture. The tetrachloride. For simplicity a circle is used to drawing should show the carbon represent the molecule. Complete the beaker on the tetrachloride on the bottom and right to illustrate the result of mixing the two liquids. the water on top, due to the difference in densities. Shown below are two beakers. One contains liquid The two liquids form a solution. hexane and the other contains liquid carbon The two components are tetrachloride. For simplicity a circle is used to uniformly distributed represent the molecule. Complete the beaker on the throughout the solution. right to illustrate the result of mixing the two liquids. -
Stoichiometric Control of DNA-Grafted Colloid Self-Assembly
Stoichiometric control of DNA-grafted colloid self-assembly Thi Voa, Venkat Venkatasubramaniana, Sanat Kumara,1, Babji Srinivasanb, Suchetan Pala,c, Yugang Zhangc, and Oleg Gangc aDepartment of Chemical Engineering, Columbia University, New York, NY 10027; bDepartment of Chemical Engineering, Indian Institute of Technology, Gandhinagar 382424, India; and cCenter for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973 Edited by Monica Olvera de la Cruz, Northwestern University, Evanston, IL, and approved March 3, 2015 (received for review October 31, 2014) There has been considerable interest in understanding the self- reinforces the commonly held view that the desired crystal will only assembly of DNA-grafted nanoparticles into different crystal struc- form if the right stoichiometry is used. tures, e.g., CsCl, AlB2, and Cr3Si. Although there are important Similarly, several coarse-grained models also allow for the exceptions, a generally accepted view is that the right stoichiometry rapid determination of the crystal structure formed by binary of the two building block colloids needs to be mixed to form the mixtures of DNA-grafted colloids (23–25). The complementary desired crystal structure. To incisively probe this issue, we combine contact model (CCM) is a canonical example of such a coarse- experiments and theory on a series of DNA-grafted nanoparticles at grained description (23). Inspired by experiments, this theory varying stoichiometries, including noninteger values. We show that assumes that only attractive energetics (derived from DNA stoichiometry can couple with the geometries of the building blocks base pairing) determine the standard-state free energy. Thus, to tune the resulting equilibrium crystal morphology. As a concrete the CCM ignores any repulsive interactions. -
Arxiv:Cond-Mat/0602428V1
Ground-State Shapes and Structures of Colloidal Domains Jianlan Wu and Jianshu Cao∗ Department of Chemistry, Massachusetts Institute of Technology Cambridge, MA 02139 (Dated: First submitted August 21, 2004) Abstract In charged colloidal suspensions, the competition between square-well attraction and long-range Yukawa repulsion leads to various stable domains and Wigner supercrystals. Using a continuum model and symmetry arguments, a phase diagram of spheres, cylinders, and lamellae is obtained as a function of two control parameters, the volume fraction and the ratio between the surface tension and repulsion. Above a critical value of the ratio, the microphase cannot be supported by the Yukawa repulsion and macroscopic phase separation occurs. This finding quantitatively explains the lack of pattern formation in simple liquids because of the small hard sphere diameter in comparison with the size of macromolecules. The phase diagram also predicts microphase separation at zero value of the ratio, suggesting the possibility of self-assembly in repulsive systems. PACS numbers: 82.70.Dd, 05.65.+b, 64.70.-p arXiv:cond-mat/0602428v1 [cond-mat.soft] 17 Feb 2006 ∗ Email: [email protected] 1 Microphase separation is ubiquitous in soft matter systems[1, 2, 3, 4, 5, 6, 7, 8]. For example, microphase separation in block copolymers results from mixing of two or more chemically different polymer segments[3]. Competition of hydrophobic and hydrophilic head- groups of amphiphiles leads to micelles in the water solution[4]. The self-assembly processes in charged colloidal suspensions and protein solutions can lead to the formation of stable domains and Wigner supercrystals (see Fig. -
Computational Modelling of Solvent Effects in a Prolific
Faraday Discussions Cite this: Faraday Discuss.,2018,211,383 View Article Online PAPER View Journal | View Issue Computational modelling of solvent effects in a prolific solvatomorphic porous organic cage† David P. McMahon,a Andrew Stephenson,b Samantha Y. Chong, b Marc A. Little, b James T. A. Jones,‡b Andrew I. Cooper *b and Graeme M. Day *a Received 16th February 2018, Accepted 22nd March 2018 DOI: 10.1039/c8fd00031j Crystal structure prediction methods can enable the in silico design of functional Creative Commons Attribution 3.0 Unported Licence. molecular crystals, but solvent effects can have a major influence on relative lattice energies, sometimes thwarting predictions. This is particularly true for porous solids, where solvent included in the pores can have an important energetic contribution. We present a Monte Carlo solvent insertion procedure for predicting the solvent filling of porous structures from crystal structure prediction landscapes, tested using a highly solvatomorphic porous organic cage molecule, CC1. Using this method, we can understand why the predicted global energy minimum structure for CC1 is never observed from solvent crystallisation. We also explain the formation of three different This article is licensed under a solvatomorphs of CC1 from three structurally-similar chlorinated solvents. Calculated solvent stabilisation energies are found to correlate with experimental results from thermogravimetric analysis, suggesting a future computational framework for a priori Open Access Article. Published on 16 April 2018. Downloaded 10/2/2021 4:27:46 PM. materials design that factors in solvation effects. Introduction A fundamental goal for computational chemistry is the in silico design of func- tional materials.