The truth is that atoms do not exist as single points that are either wholly positive or wholly negative, as in the hard-sphere model. What is the lattice energy of CaCl2? - Answers Unfortunately, some of the factors for both the Born-Land and Born-Mayer equations require either careful computation or detailed structural knowledge of the crystal, which are not always easily available to us. Hence, ionic bond results when there is transferring of electron (s) either from one atom to another atom or from metal to nonmetal. The compound does not dissolve in water. It has ions with the largest charge. I also have, The enthalpy of formation of MX is Hf = 457 kJ/mol. The basis of these models are, One of most common crystal model is so-called, Data within first table (ion pairs) come from. Therefore. Ca(g) --> Ca^+ + e dH = + 589.5 kJ Energy needed to vaporize one mole of Ca (s) is 192 kJ. Still, if you would like us to add some more, please feel free to write to us . Answered: (a) Based on the lattice energies of | bartleby Housecroft, Catherine E. and Alan G. Sharpe. Legal. IP of Na(g) = 496 (Ionization potential or energy) LiF, NaF, CaF2, AlF3. Let us understand the formation of calcium chloride in detail. The other definition says that lattice energy is the reverse process, meaning it is the energy released when gaseous ions bind to form an ionic solid. Find more about crystallography with our cubic cell calculator! Therefore, the first step would be the dissociation of chlorine elements into chlorine atoms and the next step would be acceptance of electrons. That immediately removes any possibility of confusion. First, he found that **in most cases was equal to 0.345pm0.345\ \text{pm}0.345pm, and so replaced it by ddd, equal to 3.451011m3.45\times10^{11}\ \text{m}3.451011m. Next, he replaced the measured distance between ions, r0r_0r0, with merely the sum of the two ionic radii, r++rr^++r^-r++r. Lattice Energy: The Born-Haber cycle is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by LibreTexts. Crystal Structures: Lattices and Solids in Stereoview. Kapustinskii, a Soviet scientist, also noticed this and decided to make some improvements to the Born-Mayer equation to make it more fit for general purpose. Calcium chloride is prepared by reaction of calcium hydroxide with hydrogen chloride. Use an enthalpy diagram to calculate the lattice energy of CaCl2 from Study with Quizlet and memorize flashcards containing terms like Beryllium forms a compound with chlorine that has the empirical formula BeCl2. Work Plz. Atoms can come together in many different ways, and this lattice energy calculator is concerned with the energy stored when cations and anions ionically bond as a part of a larger, uniform structure. This is the energy of the ionic solid, and will be used at the end of the process to determine the lattice energy. Hi everyone for this problem we're told the lattice energy of sodium iodide is 682 kg per mole, while that of sodium chloride is 788 kg joules per mole. The ionic and covalent bonds can be differentiated on the basis of the electronegativity difference of the bond between atoms. The lattice energy (U) of the calcium chloride is . Name the major nerves that serve the following body areas? For calcium, the first IE = 589.5 kJ mol-1, the second IE = 1146 kJ mol-1. Lattice energy is defined as the energy released during the conversion of gaseous ions into their corresponding solid ions. Lattice Energy - Chemistry LibreTexts and hence, the calcium atom will lose its electron easily. Lime, CaO, is know to have the same structure as NaCl and the edge length of the unit cell for CaO is 481 pm. CaCO3 + 2NaCl CaCl2 + Na2CO3, Calcium chloride produces free calcium ions i.e., the aqua complex of calcium ion and chloride ion by dissolving themselves in water as follows, CaCl2 + 6H2O > [Ca(H2O)6]2+ + 2Cl. The values used in the Born-Haber Cycle are all predetermined changes in enthalpy for the processes described in the section above. ---------------------------------- Ca^+(g) --> Ca^2+ + e dH = + 1146 kJ 2*Cl(g) + 2e -->2*Cl^-(g) dH =2*-348 kJ Some might expect such an ordered structure to be less stable because the entropy of the system would be low. In one definition, the lattice energy is the energy required to break apart an ionic solid and convert its component atoms into gaseous ions. (1) M a L b ( s) a M b + ( g) + b X a ( g) This quantity cannot be experimentally determined directly, but it can be estimated using a Hess Law approach in the form of Born-Haber cycle. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); Address: 9241 13th Ave SW How Calcium Chloride is an Ionic compound? Metals exist in nature as single atoms and thus no dissociation energy needs to be added for this element. Required fields are marked *. This reaction results in an appreciable increase in temperature i.e., exothermic reaction, and hence, dissolution of calcium chloride in water has a high enthalpy of solvation. Which one of the following has the greatest lattice energy? Ca2+ (g) + 2Cl-(g) CaCl2 (s) + U. Discussion:This number has not been checked. The size of the lattice energy is connected to many other physical properties including solubility, hardness, and volatility. Calculate the lattice energy of Cacl2 given that the heat of sublimation of Ca=121 kJ/mol and Hf Cacl2=-795. This has been going on for about a week Every time I try to watch a video on Youtube from my laptop I get instantly redirected to "gslbeacon.ligit.com." 2 k J m o l -. Now, one calcium ion will combine with two chlorine ions, and hence, ionic bond formation takes place between them by releasing energy. where can i find red bird vienna sausage? Next, the electron affinity of the nonmetal will be subtracted from the previous value. For the reverse process of Equation \ref{eq1}: \[\ce{ a M^{b+} (g) + b X^{a-} (g) \rightarrow M_{a}L_{b}(s) }\]. Corrundum Al2O3 has some covalent character in the solid as well as the higher charge of the ions. Determine the energy of the metal and nonmetal in their elemental forms. Substituting this new approximation into the Born-Land equation gives: Since then, further improvements in our understanding of the universe have lead to a more accurate repulsion term, which in turn have given better equations for how to calculate lattice energy. No creo que Susana _____ (seguir) sobre los consejos de su mdico. However, this sharing may be equal or unequal depending on the electronegativity of the constituent atoms of the molecules. Calculate the enthalpy of solution per mole of solid CaCl2. Hsub of Na = 108 kJ/mol (Heat of sublimation) Rearrangement to solve for lattice energy gives the equation: Lattice energy= Heat of formation- Heat of atomization- Dissociation energy- (sum of Ionization energies)- (sum of Electron Affinities). Born-Land equation While the hard-sphere model is a useful approximation, it does have some issues. Why is CaCl2 more soluble in water than CaF2? - Quora The crystal lattice energy has influence on other physical and chemical properties: solubility, volatility, melting temperature (the higher lattice energy, the higher melting temperature), hardness, etc. 3 Answers C5H5N in water > C5H5NH+ & OH- Kb = [C5H5NH+] [OH-] / [C5H5N] 1.5e-9 = [x] 1. The first major improvement came from Mayer, who found that replacing 1/rn1/r^n1/rn with ere^{-\frac{r}{\rho}}er yielded a more accurate repulsion term. The calcium ion and chlorine ion attract each other via electrostatic force of attraction and an ionic bond formation takes place between them by releasing energy in the form of Lattice energy. 2. Mi hermana se sorprende N-F C-F Cl-F F-F 2 Answers C-F is the most polar. Perhaps surprisingly, there are several ways of finding the lattice energy of a compound. Spanish Help Journal of Chemical Education. It is this that causes ionic solids to have such high melting and boiling points. This is a geometrical factor, depending on the arrangement of ions in the solid. Hence, calcium chloride is an ionic compound. Cl2(g)--> 2Cl(g) dH = 242.6 kJ What is the lattice energy of calcium chloride? - BYJUS where N is the Avogadro's number (6.022x10-23), and n is a number related to the electronic configurations of the ions involved. Ladd, Mark. (Na)=495 kJ/mol Bond Energy (O2) = 495 kJ/mol E.A. Use an enthalpy diagram to calculate the lattice energy of CaCl2 from the following information. The value calculated for U depends on the data used. A lot of energy is released as the oppositely charged ions interact. Okay, so let's recall what lattice energy is. Some are given here. The lattice energies for NaCl most often quoted in other texts is about 765 kJ/mol. Ladd, Mark. Two over R. And lattice energy. It is an inorganic . Socks Loss Index estimates the chance of losing a sock in the laundry. LiCl, NaCl, CaCl2, Al2O3. For example, using the Kapustinskii equation, the lattice energy of NaCl\text{NaCl}NaCl is 746kJ/mol746\ \text{kJ}/\text{mol}746kJ/mol, while the lattice energy of CaO\text{CaO}CaO is 3430kJ/mol3430\ \text{kJ}/\text{mol}3430kJ/mol. However, when plugging in a value, determine whether energy is released (exothermic reaction) or absorbed (endothermic reaction) for each electron affinity. Size of the ion On comparing the four given compounds we can see that, M gO and CaO have higher charges (+2 and -2 on the cations and anions respectively) than N aCl and KCl (+1 and -1 on the cations and anions respectively). In India on the occasion of marriages the fireworks class 12 chemistry JEE_Main, The alkaline earth metals Ba Sr Ca and Mg may be arranged class 12 chemistry JEE_Main, Which of the following has the highest electrode potential class 12 chemistry JEE_Main, Which of the following is a true peroxide A rmSrmOrm2 class 12 chemistry JEE_Main, Which element possesses the biggest atomic radii A class 11 chemistry JEE_Main, Phosphine is obtained from the following ore A Calcium class 12 chemistry JEE_Main, Differentiate between the Western and the Eastern class 9 social science CBSE, NEET Repeater 2023 - Aakrosh 1 Year Course, CBSE Previous Year Question Paper for Class 10, CBSE Previous Year Question Paper for Class 12. How would the energy of the ionic bond be affected by the following changes? The positive ions experience both attraction and repulson from ions of opposite charge and ions of the same charge. Lattice energy can be defined as the energy required to convert one mole of an ionic solid into gaseous ionic constituents. Deltoid muscle _____ 2. Add the changes in enthalpy to turn one of the elements into its gaseous state, and then do the same for the other element. Skill:Explain the trend of lattice energy. The other trend that can be observed is that, as you move down a group in the periodic table, the lattice energy decreases. 2003-2023 Chegg Inc. All rights reserved. Discussion After this, it was shown that the Madelung constant of a structure divided by the number of atoms in the structure's empirical formula was always roughly equal (0.85\sim0.850.85), and so a constant to account for this could be used to replace the Madelung constant. As there is the formation of cations and anion, there will be the electrostatic force of attraction between them. The n values and the electronic configurations (e.c.) Calculate the lattice enegry of CaCl 2 from the given data. Chem Chapter 9 Flashcards | Quizlet KF MgS RbI Is there a formula or some simple way of knowing which has the greatest energy? Boston: Birkhauser, 2005. For these reasons they have not been included in the present lattice energy calculator. Therefore, the hard-sphere equation for lattice energy is: While the hard-sphere model is a useful approximation, it does have some issues. Evaluate the energy of crystallization, Ecryst for CaO. As we know that the calcium atom belongs to group 2 of the modern periodic table and hence, it is a metal. Hf of NaCl = -411 (Enthalpy of formation). Chichester: Horwood, 1999. Seattle, Washington(WA), 98106. Suzuki, Takashi. How to Calculate the Lattice Energy of CaCl 2: The Born-Haber cycle and Hess's Law can be used to calculate the lattice energy of an ionic crystal. Ea for F = -328 E11 forCs = +375.7 E12 for Cs = +2422 Heat of sublimation for Cs =, Na+(g) + Br-(g) --> NaBr (s) Hint: use the Born-Haber cycle Note: the reference state for Br2 is Br2(l) not Br2(g) Data (in kJ/mol): enthalpy of sublimation of Na(s): 107 standard enthalpy, I have to place the following in order of decreasing magnitude of lattice energy, but I don't know how to do it. First equal the formation enthalpy to the sum of all the other enthalpy's and use letter X to represent the lattice enthalpy . A highly concentrated solution of calcium chloride on the road prevents the formation of the dust owing to its hygroscopic nature and forming a liquid layer on the surface of the road. Ca2+(g) +2e- +2Cl(g) (up arrow) enthalpy ionisation down arrow electron affinity Ca+(g) + e- +2Cl(g) Ca2+(g) +2Cl-(g) (up arrow) enthalpy ionisation down arrow lattice enthalpy Ca(g) +2Cl(g) (up arrow) enthalpy atomisation Ca(g) +Cl2(g) (up arrow) enthalpy atomisation Ca (s) +Cl2(g) down arrow) enthalpy formation CaCl2(S) Lattice enthalpy = enthalpy formation enthalpy atomisation for calcium 2x enthalpy atomisation for chlorine-1st and second ionisation energies for calcium electron affinity for Clx2, Your email address will not be published. The Lattice energy, U, is the amount of energy required to separate a mole of the solid (s) into a gas (g) of its ions. DeltaHf (Na2O (s))=-414kJ/mol Delta H sublimation(Na)=109 kJ/mol I.E. Your email address will not be published. The Born-Haber cycle allows us to understand and determine the lattice energies of ionic solids. Even though this is a type of potential energy, you can't use the standard potential energy formula here. Evaluate the energy of crystallization, Ecryst . In this case, \rho is a factor representing the compressibility of the lattice, and letting this term equal 30pm30\ \text{pm}30pm is sufficient for most alkali metal halides. This has led many people to look for a theoretical way of finding the lattice energy of a compound. What is the lattice energy of Calcium Chloride? - Vedantu \(Z\) is the number of charges of the ions, (e.g., 1 for NaCl). Though Li+ is smaller than Mg2+, as the positive charge of Mg2+ is double of Li+, charge/radius ratio of Mg2+ is greater than that of Li+. The crystal lattice energy has influence on other physical and chemical properties: melting temperature (the higher lattice energy, the higher melting temperature), The science, which deals with crystals properties is, There are theroretical models, which allow to calculate (with better or worse result) the lattice energy. Save my name, email, and website in this browser for the next time I comment. The chemical bond is formed by the participation of only valence electrons, electrons of the outermost shell, of the atom. Diaphragm _____ 3. *This is a common error due to confusion caused by the definition of electron affinity, so be careful when doing this calculation. The heat energy released when new bonds are made between the ions and water molecules is known as the hydration enthalpy of the ion. Now the metal and nonmetal will be combined to form the ionic solid. The value for the lattice energy is the difference between the value from Step 1 and the value from Step 4. Lattice Enthalpies and Born Haber Cycles - Chemistry LibreTexts (O) = -141 kJ/mol E.A. The starting point for such a model is the potential energy between two gaseous ions: Two alterations are necessary to make the above equation suitable for a mole of a lattice. Lattice Energy and Enthalpy - Definition, Detailed Explanation - BYJUS Calculate the lattice energy of CaCl 2 using a Born-Haber cycle and data from Appendices F and L and Table 7.5. \[ E_{cryst} = \dfrac{N Z^2e^2}{4\pi \epsilon_o r} \left( 1 - \dfrac{1}{n} \right)\label{6.13.3a} \]. Therefore, the hard-sphere equation for lattice energy is: U=\frac {N_ {\text {A}}z^+z^-e^2 M} {4\pi\varepsilon_0r_0} U = 40r0N Az +z e2M where: N_ {\text {A}} N A Avogadro's number; and M M Madelung constant. Electron affinity : Cl (g) + e- Cl-(g) H 3 = -355 KJ mol-1 = -788 kJ/mol. 82, P. 950-952. There are two types of chemical bonds based on their formation. Calculate the lattice energy of Cacl2 given that the heat of sublimation of Ca=121 kJ/mol and Hf Cacl2=-795 first ionization of ca = 589.5 second ionization of ca = 1145 the electron affinity of Cl = 349 the cl2 bond energy is 242.7 I have found all information that i believe are needed to Combs, Leon. (b) Using data from Appendix C, Figure 7.9, and Figure 7.11 and the value of the second ionization energy for Ca,1145kJ/mol. Experts are tested by Chegg as specialists in their subject area. Calcium chloride is highly soluble in water owing to its ionic nature. 5 Answers There is no word like addressal. After this, the amount of energy you put in should be the lattice energy, right? CALCULLA - Table of lattice energy values If we then add together all of the various enthalpies (if you don't remember the concept, visit our enthalpy calculator), the result must be the energy gap between the lattice and the ions. - The lattice energy definition, How to calculate lattice energy - The lattice energy formula. Lattice energy is often used to estimate the strength of an ionic bond. 2nd Ionization Energy of Ca = 1145 $ kJ $ Bond Energy of Cl2 = 242.7 $ kJ $ Electron Affinity for chlorine = 2 $ \times $ (349 $ kJ $ ) Standard Enthalpy of Formation of CaCl2 (s) = 795 $ kJ $ We can substitute these values in the equation to find out the lattice energy So, is CaCl2 Ionic or Covalent? Here, we have discussed the ionic nature of calcium chloride. The enthalpies of formation of the ionic molecules cannot alone account for this stability. Lattice Energy is a type of potential energy that may be defined in two ways. CaCl2, referred to as calcium chloride, is a member of alkaline earth metal halides i.e., MX2, where, M is an alkaline earth metal. The Born-Haber cycle to evaluate Elattice is shown below: Ecryst = -411-(108+496+244/2)-(-349) kJ/mol Reference for second table (theoretical and BHFC values) is. [References) CHEMWORK The lattice energy of CaCl, is-2247 kJ/mol, and the enthalpy of hydration of one mole of gaseous Ca2+ and two moles of gaseous Cl" ions is -2293 kJ/mol. There are many other factors to be considered such as covalent character and electron-electron interactions in ionic solids. In order to use the Born-Haber Cycle, there are several concepts that we must understand first. Now, the calcium cation and the chlorine anions are attracted by the electrostatic force of attraction and hence, there is the formation of an ionic bond between these two atoms. The lattice energy of CaO is 3460 kJ/mol. Chichester: Horwood, 1994. Solid State Chemistry. Lattice energy - Wikipedia Before we get to grips with finding the lattice energy, it's important to know the lattice energy definition as it is quite peculiar. However, many nonmetals will exist as polyatomic species. Calcium chloride has cation Ca 2 + and two anions of Chlorine Cl -. Ionization : Ca (g) Ca 2+ (g) + 2e-H 2 = + 242.8 KJ mol-1 . The ionic solid CaCl would have the largest lattice energy. Vol. The values of the lattice energy for MgCl2, CaCl2, and SrCl2 are 2522 kJ/mol, 2253 kJ/mol, and 2127 kJ/mol, respectively. Expert Answer 100% (2 ratings) (14) Lattice energy values are, CaF2 = 2611 kJ/mol CaCl2 = 2195 kJ/mol CaO = 3464 kJ/mol CaS = 3093 kJ/mol The decreasing order of lattice enrgies, CaO > CaS > CaF2 > CaCl2 Theoretical Reason: More is the char View the full answer In chemistry, the lattice energy is the energy change upon formation of one mole of a crystalline ionic compound from its constituent ions, which are assumed to initially be in the gaseous state.It is a measure of the cohesive forces that bind ionic solids. The lattice energy is the total potential energy of the crystal. They are instead surrounded by a number of electron orbitals regardless of charge (unless you have managed to remove all of the electrons, as in the case of H+\text{H}^+H+, of course). Skill:Evaluate the lattice energy and know what values are needed. to the empployees was very informative. calculate the lattice energy of CaCl2. The hydration enthalpy is the enthalpy change when 1 mole of gaseous ions dissolve in sufficient water to give an infinitely dilute solution. Let us initiate this discussion with the basics of chemical bonds i.e., Ionic and Covalent Bond. I am Savitri,a science enthusiast with a passion to answer all the questions of the universe. Calculate the lattice enegry of CaCl2 from the given data Ca(s The first attempt was to find the sum of all of the forces, both attractive and repulsive, that contribute to the potential lattice energy. The energy to break 1 mole of a lattice at the standard temperature and pressure is defined as the standard lattice energy. Dr. Leon L. Combs. I have found all information that i believe are needed to solve this question .. yet i dont know how to solve the question! THIS QUESTION IS BASED UPON BORN HABER CYCLE, ca(s) + cl2(g) __ Cacl2 now deltaHf = 795 kj/mol, total ionisation enthalpy = 589.5 + 1145 = 1734.5 kj/mol, total bond dissociation enthalpy = 242.7 kj/mol, we have two cl atoms so electron gain enthalpy for two atoms is = 2*(-349) = -698 kj/mol as electron gain enthalpy = -(electron affinity), enthalpy of formation = enthalpy of sublimation + ionisation enthalpy + bond dissociation enthalpy + electron gain enthalpy + lattice enthalpy, -795 = 1734.5+121+242.7-698+lattice enthalpy, so lattice enthalpy = -795 1400.2 = 2195.2 kj/mol, I have found all information that i believe are needed to, For the best answers, search on this site https://shorturl.im/jHX2X, You will need to draw a born harbour cycle. B)Enter the the Ksp expression forC2D3 in terms of the molar solubility x. Jimmy aaja -M.I.A. Is CaCl2 Ionic or Covalent? - Techiescientist For example: 7*x^2. Comparing the lattice energies of the three salts, students could now be asked to look at the relative strengths of the bonds in the compounds to relative sizes of ions and relative charge on ions. These compounds have an additional stability due to the lattice energy of the solid structure. We need to estimate the lattice energies of sodium bromide. The enthalpy of sublimation of M is Hsub = 121 kJ/mol. Chemists, for various reasons, like to have exact and sometimes unintuitive definitions, but they do serve a purpose, we assure you. The ionization energy of M is IE = 433 kJ/mol. Calculate the lattice energy of Cacl2? The lattice energy (U) of the calcium chloride is -2195 kJ/mol. It is, however, still an approximation, and improvements to the repulsion term have since been made. "Thermodynamics of the Relationship between Lattice Energy and Lattice Enthalpy." As the ionic radii of either the cation or anion increase, the lattice energies decrease. Hess' Law allows us to add or subtract these values, which allows us to determine the lattice energy. Chemical Bonding in Solids and Fluids. These additional reactions change the total energy in the system, making finding what is the lattice energy directly difficult. Can I use this word like this: The addressal by the C.E.O. the energy released is called energy of crystallization (\(E_{cryst}\)). The lattice energy is usually given in kilojules per mole (kJ/mol). Its values are usually expressed with the units kJ/mol. Lattice energy depends on two important factors. For calcium the first ionization energy is 589.5kJ/mol and the second ionization energy is 1146kJ/mol. The Born-Haber Cycle can be reduced to a single equation: Heat of formation= Heat of atomization+ Dissociation energy+ (sum of Ionization energies)+ (sum of Electron affinities)+ Lattice energy. How Ionic Bond formation takes place in Calcium Chloride, Differentiation between Ionic and Covalent bond. Table 8.2 Figure 7.9 11 Uses of Platinum Laboratory, Commercial, and Miscellaneous, CH3Br Lewis Structure, Geometry, Hybridization, and Polarity. As an example, let us consider the the NaCl crystal. In this simple view, appropriate number of cations and anions come together to form a solid. (O -) = 878 kJ/mol Use this information to calculate the lattice energy of Na2O (s). Such as in the song Jimmy by M.I.A look at aaja in the dictionary My indian boyfriend told me is meaning come to me, 6 Answers I have never had or heard of that particular brand, but have had several here in Canada, plus a number in the Caribbean and Asia, and there all the same, small cut hot dogs in a can, no need q now please.. Name the major nerves that serve the following body areas:? Values of lattice energies for various solids have been given in literature, especially for some common solids. Step-by-step solution Step 1 of 5 The standard enthalpy of formation of an ionic solid from its constituent elements is given by Hess's Law: .. (1) In the equation, = the standard enthalpy of formation of the solid compound We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. Which one of the following ionic solids would have the largest lattice First, we can see that by increasing the charge of the ions, we will dramatically increase the lattice energy. How do you calculate lattice energy? [Answered!] - scienceoxygen.com There are other factors to consider for the evaluation of energy of crystallization, and the treatment by M. Born led to the formula for the evaluation of crystallization energy \(E_{cryst}\), for a mole of crystalline solid. Dissociation : Cl 2(g) 2Cl (g) H 3 = +242.8 KJ mol-1 . Im a mother of two crazy kids and a science lover with a passion for sharing the wonders of our universe. But for simplicity, let us consider the ionic solids as a collection of positive and negative ions. "Lattice Energy". It is an inorganic compound of white color without any odor. Note, that while the increase in r++rr^++r^-r++r in the electronic repulsion term actually increases the lattice energy, the other r++rr^++r^-r++r has a much greater effect on the overall equation, and so the lattice energy decreases. The application of these new equation are, however, still quite niche and the improvements not as significant. The formation of calcium chloride can be explained by the Born Haber cycle. Calculate the lattice energy of CaCl2 from the given data Ca A ( s) + Cl A 2 A ( g) CaCl A 2 A ( s) H f H f 0 = 795 kJ mol 1 Sublimation: (g) Ca A ( s) Ca (g) H H 1 0 = + 121 kJ mol 1 Ionisation: Ca A ( g) Ca A 2 + A ( g) + 2 e A H H 2 0 = + 2422 kJ mol 1 Dissociation: Cl A 2 A ( g) 2 Cl A ( g) H H 3 0 = + 242.8 kJ mol 1 Lattice Energy is used to explain the stability of ionic solids.