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Thermodynamics

A-Level AQA Chemistry

This flashcard pack covers key concepts related to thermochemistry and reaction energetics, including various types of enthalpy changes (formation, atomisation, bond dissociation, ionisation, electron affinity, lattice formation), the Born-Haber cycle, Gibbs free energy, entropy, and factors affecting reaction feasibility. It also addresses the calculation of standard entropies, the relationship between entropy, enthalpy, and temperature in chemical reactions, and the thermodynamics of phase changes and solubility.

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"How can the temperature at which a reaction becomes feasible be calculated?"	"T = H / S"
"How can balanced chemical equations be used to predict the sign of entropy change?"	"Balanced chemical equations can often be used to predict if the entropy change is positive or negative."
"What are standard entropies?"	"Standard entropies (S°) are the entropies per mole for substances in their standard states."
"Can a substance have a standard entropy less than zero?"	"No, it is not possible for a substance to have a standard entropy less than zero."
"Describe the relationship between entropy and enthalpy in determining the feasibility of a reaction."	"The balance between entropy and enthalpy determines the feasibility of a reaction."
"Define Gibbs free energy."	"Gibbs free energy is a term that combines the effect of enthalpy and entropy into one number."
"What is the equation for Gibbs free energy change?"	"G = H - T S"
"How does increasing entropy and exothermicity affect the feasibility of a reaction?"	"A reaction that has increasing entropy (+ve S) and is exothermic (-ve H) will make G negative and always be feasible."
"What is the condition for a reaction to be feasible?"	"If G is negative, the reaction is feasible, but there is still a possibility that it may not occur or occur very slowly."
"What can cause a positive entropy change?"	"A change of state from solid or liquid to gas, or a significant increase in the number of molecules between products and reactants."
"Describe the relationship between Gibbs free energy and phase changes."	"During phase changes, the Gibbs free energy for such changes is zero."
"Describe the effect of temperature on the feasibility of a reaction involving an increase in entropy."	"Increasing temperature makes it more likely for the reaction to occur, as it makes the value of -TS in the equation G = H - TS more negative."
"Describe the effect of temperature on the feasibility of a reaction involving a decrease in entropy."	"Increasing temperature makes it less likely for the reaction to occur, as -TS will be small and G will not change much."
"Define the enthalpy of lattice dissociation."	"The enthalpy of lattice dissociation is the energy needed to break up the lattice of an ionic substance and convert it into gaseous ions."
"Describe the relationship between the size and charge of an ion and the strength of the lattice enthalpy."	"The smaller the ion and the higher its charge, the stronger the lattice enthalpy."
"Describe the enthalpy of solution of NaCI."	"The enthalpy of solution of NaCI is the energy change that occurs when NaCI dissolves in water."
"What is the relationship between hydration enthalpies and energy?"	"Hydration enthalpies are exothermic as energy is given out when water molecules bond to the metal ions."
"Define lattice enthalpy of formation."	"The lattice enthalpy of formation is the energy change that occurs when one mole of a compound is formed from its constituent ions in the gas phase."
"How does the charge density of ions affect their hydration enthalpy?"	"The higher the charge density, the greater the hydration enthalpy, as the ions attract the water molecules more strongly."
"Describe the solubility of a substance based on its H solution."	"In general, a substance is more likely to be soluble if the H solution is exothermic. If H solution is endothermic, the substance may be insoluble if the lattice enthalpy is much larger than the hydration enthalpy."
"Describe the enthalpy of atomisation."	"The enthalpy change when 1 mole of gaseous atoms is formed from the element in its standard state."
"What is bond dissociation enthalpy?"	"The standard molar enthalpy change when one mole of a covalent bond is broken into two gaseous atoms or free radicals."
"Explain first ionisation enthalpy."	"The enthalpy change required to remove 1 mole of electrons from 1 mole of gaseous atoms to form 1 mole of gaseous ions with a +1 charge."
"What is the second ionisation enthalpy?"	"The enthalpy change required to remove 1 mole of electrons from one mole of gaseous 1+ ions to produce one mole of gaseous 2+ ions."
"Describe the first electron affinity."	"The enthalpy change that occurs when 1 mole of gaseous atoms gain 1 mole of electrons to form 1 mole of gaseous ions with a -1 charge."
"Explain the second electron affinity."	"The enthalpy change when one mole of gaseous 1- ions gains one electron per ion to produce gaseous 2- ions."
"What is the enthalpy of lattice formation?"	"The standard enthalpy change when a lattice is formed from its constituent ions in their gaseous states."
"Describe the process of calculating the lattice enthalpy using a Born-Haber cycle."	"The lattice enthalpy is calculated by linking together changes for which data are available and applying Hess's law."
"What is the purpose of a Born-Haber cycle?"	"The purpose of a Born-Haber cycle is to calculate the lattice enthalpy of a compound indirectly."
"Define lattice enthalpy."	"Lattice enthalpy is the energy released when one mole of an ionic compound is formed from its gaseous ions."
"How can the lattice enthalpy be determined indirectly?"	"The lattice enthalpy can be determined indirectly by using a Born-Haber cycle and linking together changes for which data are available."
"Define enthalpy change of formation."	"The energy transferred when 1 mole of a compound is formed from its elements under standard conditions (298K and 100kPa), with all reactants and products in their standard states."
"How does the ionization energy affect the enthalpy of formation in the Born Haber cycle?"	"The ionization energy contributes to the enthalpy of formation in the Born Haber cycle by balancing the lattice enthalpy."
"Describe the stability of CaCl2 compared to CaCI and CaCI3."	"CaCl2 is the most stable form as it has the most exothermic enthalpy of formation compared to CaCI and CaCI3."
"What is a spontaneous process?"	"A process that proceeds on its own without any external influence."
"What is activation energy?"	"The energy required to start a reaction."
"Describe the relationship between exothermic reactions and thermodynamic stability."	"Exothermic reactions result in products that are more thermodynamically stable than the reactants."
"What is entropy?"	"Entropy is a description of the number of ways atoms can share quanta of energy."
"How does the entropy of substances with more ways of arranging their atoms and energy compare to substances with fewer ways?"	"Substances with more ways of arranging their atoms and energy have higher entropy."
"What is the relationship between the entropy of solids, liquids, and gases?"	"Solids have lower entropies than liquids, which are lower than gases."
"What happens to the entropy of a solid as its temperature increases?"	"The entropy of a solid increases as its temperature increases."
"What is the relationship between boiling and entropy?"	"There is a bigger jump in entropy with boiling than with melting."

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How can the temperature at which a reaction becomes feasible be calculated?

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T = H / S

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[{"id":974869,"front":"How can the temperature at which a reaction becomes feasible be calculated?","back":"T = H / S","front_language":"English","back_language":"English","front_image":"","back_image":"","order":0,"explanation":"The equation T = H / S is known as the Gibbs free energy equation. It relates the temperature (T) at which a reaction becomes feasible to the enthalpy change (H) and the entropy change (S) of the system. The enthalpy change represents the heat energy released or absorbed during the reaction, while the entropy change represents the disorder or randomness of the system. By calculating the ratio of H to S, we can determine the temperature at which the reaction becomes feasible.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974857,"front":"How can balanced chemical equations be used to predict the sign of entropy change?","back":"Balanced chemical equations can often be used to predict if the entropy change is positive or negative.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":1,"explanation":"Balanced chemical equations provide information about the stoichiometry of a reaction, including the number and types of molecules involved. Entropy change is related to the number of possible arrangements of particles in a system. If the number of particles increases in the products compared to the reactants, it suggests an increase in entropy (positive change). Conversely, if the number of particles decreases, it suggests a decrease in entropy (negative change). By examining the balanced equation, one can determine if the reaction involves an increase or decrease in the number of particles, thus predicting the sign of the entropy change.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974860,"front":"What are standard entropies?","back":"Standard entropies (S°) are the entropies per mole for substances in their standard states.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":2,"explanation":"Standard entropies, denoted as S°, are a measure of the disorder or randomness of a substance in its standard state. They are expressed in units of joules per mole per kelvin (J/mol·K). Standard entropies provide information about the number of possible microstates or arrangements of particles in a system. Higher standard entropies indicate greater disorder and a larger number of possible arrangements. Standard entropies are useful in thermodynamics and can be used to calculate changes in entropy during chemical reactions or phase transitions.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974861,"front":"Can a substance have a standard entropy less than zero?","back":"No, it is not possible for a substance to have a standard entropy less than zero.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":3,"explanation":"No, a substance cannot have a standard entropy less than zero. Standard entropy is a measure of the disorder or randomness of a substance at a specific temperature. Since disorder and randomness cannot be negative, the standard entropy of a substance cannot be less than zero.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974862,"front":"Describe the relationship between entropy and enthalpy in determining the feasibility of a reaction.","back":"The balance between entropy and enthalpy determines the feasibility of a reaction.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":4,"explanation":"The relationship between entropy and enthalpy is crucial in determining the feasibility of a reaction. Entropy refers to the degree of disorder or randomness in a system, while enthalpy represents the heat energy involved in a reaction. For a reaction to be feasible, the increase in entropy must outweigh the increase in enthalpy. This means that the system becomes more disordered and the energy released is greater than the energy required. The balance between these two factors ultimately determines whether a reaction will occur spontaneously.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974863,"front":"Define Gibbs free energy.","back":"Gibbs free energy is a term that combines the effect of enthalpy and entropy into one number.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":5,"explanation":"Gibbs free energy is a thermodynamic potential that measures the maximum amount of reversible work that can be performed by a system at constant temperature and pressure. It takes into account both the enthalpy, which represents the heat energy of a system, and the entropy, which represents the disorder or randomness of a system. By combining these factors, Gibbs free energy provides insight into the spontaneity and equilibrium of a chemical reaction or physical process.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974864,"front":"What is the equation for Gibbs free energy change?","back":"G = H - T S","front_language":"English","back_language":"English","front_image":"","back_image":"","order":6,"explanation":"The equation for Gibbs free energy change, G, is derived from the enthalpy change, H, and the entropy change, S, of a system. It takes into account the temperature, T, at which the reaction occurs. The Gibbs free energy change is a measure of the spontaneity and directionality of a chemical reaction. It determines whether a reaction is thermodynamically favorable or not.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974865,"front":"How does increasing entropy and exothermicity affect the feasibility of a reaction?","back":"A reaction that has increasing entropy (+ve S) and is exothermic (-ve H) will make G negative and always be feasible.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":7,"explanation":"Increasing entropy and exothermicity both contribute to a decrease in the Gibbs free energy (G) of a reaction. This decrease in G indicates that the reaction is more likely to occur spontaneously and is therefore more feasible. Entropy represents the degree of disorder in a system, and an increase in entropy favors the formation of products. Exothermic reactions release energy, which also promotes the feasibility of the reaction. Therefore, when both entropy and exothermicity increase, the reaction becomes more favorable and feasible.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974868,"front":"What is the condition for a reaction to be feasible?","back":"If G is negative, the reaction is feasible, but there is still a possibility that it may not occur or occur very slowly.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":8,"explanation":"The condition for a reaction to be feasible is determined by the value of G, the Gibbs free energy change. If G is negative, it indicates that the reaction is thermodynamically favorable and can proceed spontaneously. However, the possibility of the reaction not occurring or occurring slowly suggests that other factors, such as activation energy or reaction kinetics, may also influence the feasibility of the reaction.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974856,"front":"What can cause a positive entropy change?","back":"A change of state from solid or liquid to gas, or a significant increase in the number of molecules between products and reactants.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":9,"explanation":"A positive entropy change can occur when there is a change of state from solid or liquid to gas. This is because the gas phase has more disorder and higher entropy compared to the condensed phases. Additionally, an increase in the number of molecules between products and reactants can also lead to a positive entropy change, as it increases the overall disorder and randomness in the system.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974871,"front":"Describe the relationship between Gibbs free energy and phase changes.","back":"During phase changes, the Gibbs free energy for such changes is zero.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":10,"explanation":"During phase changes, the Gibbs free energy remains constant, indicating that there is no change in the system's ability to do work. This is because phase changes involve a rearrangement of molecules without any change in temperature or pressure. At equilibrium, the Gibbs free energy is minimized, and any further change in the system would require an input of energy. Therefore, the Gibbs free energy for phase changes is zero, indicating a stable and balanced state.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974872,"front":"Describe the effect of temperature on the feasibility of a reaction involving an increase in entropy.","back":"Increasing temperature makes it more likely for the reaction to occur, as it makes the value of -TS in the equation G = H - TS more negative.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":11,"explanation":"Increasing temperature has a direct effect on the feasibility of a reaction involving an increase in entropy. This is because temperature is directly related to the entropy term in the Gibbs free energy equation. As temperature increases, the value of -TS becomes more negative, which in turn makes the overall Gibbs free energy (G) more negative. A more negative G indicates a more favorable reaction, making it more likely for the reaction to occur. Therefore, increasing temperature increases the feasibility of the reaction.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974873,"front":"Describe the effect of temperature on the feasibility of a reaction involving a decrease in entropy.","back":"Increasing temperature makes it less likely for the reaction to occur, as -TS will be small and G will not change much.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":12,"explanation":"Increasing temperature decreases the feasibility of a reaction involving a decrease in entropy. This is because the term -TS, which represents the change in entropy, becomes smaller at higher temperatures. As a result, the change in Gibbs free energy (ΔG) will not change significantly, making the reaction less likely to occur.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974874,"front":"Define the enthalpy of lattice dissociation.","back":"The enthalpy of lattice dissociation is the energy needed to break up the lattice of an ionic substance and convert it into gaseous ions.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":13,"explanation":"The enthalpy of lattice dissociation is a measure of the energy required to separate the ions in an ionic lattice and convert them into gaseous ions. This process involves breaking the strong electrostatic forces holding the ions together in the lattice. The enthalpy of lattice dissociation is an important parameter in understanding the stability and reactivity of ionic compounds. It can be influenced by factors such as the size and charge of the ions, as well as the arrangement of the lattice structure.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974875,"front":"Describe the relationship between the size and charge of an ion and the strength of the lattice enthalpy.","back":"The smaller the ion and the higher its charge, the stronger the lattice enthalpy.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":14,"explanation":"The size and charge of an ion play a crucial role in determining the strength of the lattice enthalpy. Smaller ions have a stronger attraction to each other due to their closer proximity, leading to a higher lattice enthalpy. Additionally, ions with higher charges have a stronger electrostatic attraction, resulting in a stronger lattice enthalpy. Therefore, the relationship between the size and charge of an ion and the strength of the lattice enthalpy is that smaller ions with higher charges have a stronger lattice enthalpy.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974877,"front":"Describe the enthalpy of solution of NaCI.","back":"The enthalpy of solution of NaCI is the energy change that occurs when NaCI dissolves in water.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":15,"explanation":"The enthalpy of solution of NaCI is a measure of the energy change that takes place when NaCI is dissolved in water. It quantifies the heat absorbed or released during the dissolution process. This value is important in understanding the solubility and the interactions between the solute and solvent molecules.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974878,"front":"What is the relationship between hydration enthalpies and energy?","back":"Hydration enthalpies are exothermic as energy is given out when water molecules bond to the metal ions.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":16,"explanation":"Hydration enthalpies represent the energy change when ions dissolve in water. Exothermic reactions release energy, indicating stability in the system. The negative enthalpy change signifies that more energy is released during hydration than required to break the initial ionic bonds.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974879,"front":"Define lattice enthalpy of formation.","back":"The lattice enthalpy of formation is the energy change that occurs when one mole of a compound is formed from its constituent ions in the gas phase.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":17,"explanation":"Lattice enthalpy of formation quantifies the energy released or absorbed during the formation of a compound from its ions in the gas phase. It reflects the stability of the ionic compound and is crucial in understanding chemical reactions and bond strengths in ionic compounds.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974880,"front":"How does the charge density of ions affect their hydration enthalpy?","back":"The higher the charge density, the greater the hydration enthalpy, as the ions attract the water molecules more strongly.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":18,"explanation":"The charge density of ions refers to the ratio of the charge of an ion to its size. When the charge density of an ion is higher, it means that the charge is more concentrated in a smaller space. This leads to a stronger attraction between the ion and water molecules during hydration. As a result, the hydration enthalpy, which measures the energy released when ions are hydrated, increases with higher charge density.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974881,"front":"Describe the solubility of a substance based on its H solution.","back":"In general, a substance is more likely to be soluble if the H solution is exothermic. If H solution is endothermic, the substance may be insoluble if the lattice enthalpy is much larger than the hydration enthalpy.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":19,"explanation":"The solubility of a substance is influenced by the enthalpy of its solution. An exothermic H solution indicates higher solubility, while an endothermic H solution suggests potential insolubility if lattice enthalpy outweighs hydration enthalpy. This is due to the energy changes during the dissolution process.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974821,"front":"Describe the enthalpy of atomisation.","back":"The enthalpy change when 1 mole of gaseous atoms is formed from the element in its standard state.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":20,"explanation":"The enthalpy of atomization is a measure of the energy required to break apart one mole of a substance into its individual atoms in the gas phase. It reflects the strength of the bonds holding the atoms together in the solid state.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974822,"front":"What is bond dissociation enthalpy?","back":"The standard molar enthalpy change when one mole of a covalent bond is broken into two gaseous atoms or free radicals.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":21,"explanation":"Bond dissociation enthalpy is a measure of the energy required to break a covalent bond. It represents the stability of a bond and is crucial in understanding chemical reactions and the strength of molecules. This value is essential in various fields, including chemistry, biochemistry, and material science.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974823,"front":"Explain first ionisation enthalpy.","back":"The enthalpy change required to remove 1 mole of electrons from 1 mole of gaseous atoms to form 1 mole of gaseous ions with a +1 charge.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":22,"explanation":"First ionization enthalpy is a measure of the energy needed to remove the outermost electron from a gaseous atom. It reflects the atom's ability to hold onto its electrons, with higher values indicating greater electron affinity. This process is crucial in understanding chemical reactivity and bonding.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974824,"front":"What is the second ionisation enthalpy?","back":"The enthalpy change required to remove 1 mole of electrons from one mole of gaseous 1+ ions to produce one mole of gaseous 2+ ions.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":23,"explanation":"The second ionization enthalpy is higher than the first due to the increased electrostatic force between the remaining electrons and the now positively charged ion. This makes it more difficult to remove a second electron compared to the first.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974825,"front":"Describe the first electron affinity.","back":"The enthalpy change that occurs when 1 mole of gaseous atoms gain 1 mole of electrons to form 1 mole of gaseous ions with a -1 charge.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":24,"explanation":"The first electron affinity is a measure of how much energy is released when an atom in the gaseous state gains an electron to form a negatively charged ion. It indicates the atom's tendency to accept an additional electron and become more stable by achieving a full outer electron shell.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974826,"front":"Explain the second electron affinity.","back":"The enthalpy change when one mole of gaseous 1- ions gains one electron per ion to produce gaseous 2- ions.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":25,"explanation":"The second electron affinity refers to the energy released or absorbed when an anion accepts an additional electron to form a doubly charged anion. This process is generally less favorable than the first electron affinity due to increased repulsion between negatively charged particles.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974827,"front":"What is the enthalpy of lattice formation?","back":"The standard enthalpy change when a lattice is formed from its constituent ions in their gaseous states.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":26,"explanation":null,"deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974829,"front":"Describe the process of calculating the lattice enthalpy using a Born-Haber cycle.","back":"The lattice enthalpy is calculated by linking together changes for which data are available and applying Hess's law.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":27,"explanation":"The process of calculating lattice enthalpy using a Born-Haber cycle involves linking available data for various changes and applying Hess's law. This allows for the determination of the lattice enthalpy through a series of interconnected steps and energy changes.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974830,"front":"What is the purpose of a Born-Haber cycle?","back":"The purpose of a Born-Haber cycle is to calculate the lattice enthalpy of a compound indirectly.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":28,"explanation":"The Born-Haber cycle is a tool used in chemistry to determine the lattice enthalpy of a compound. It involves a series of steps that allow for the indirect calculation of this energy, which is difficult to measure directly. By considering various enthalpy changes, the Born-Haber cycle provides a systematic approach to determining the lattice enthalpy, which is crucial for understanding the stability and properties of ionic compounds.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974832,"front":"Define lattice enthalpy.","back":"Lattice enthalpy is the energy released when one mole of an ionic compound is formed from its gaseous ions.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":29,"explanation":null,"deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974833,"front":"How can the lattice enthalpy be determined indirectly?","back":"The lattice enthalpy can be determined indirectly by using a Born-Haber cycle and linking together changes for which data are available.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":30,"explanation":"The lattice enthalpy, which is the energy released when gaseous ions form a solid lattice, can be determined indirectly using a Born-Haber cycle. This cycle allows us to link together various changes, such as ionization energy, electron affinity, and enthalpy of formation, for which data are available. By carefully analyzing these changes and their relationships, the lattice enthalpy can be calculated indirectly.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974820,"front":"Define enthalpy change of formation.","back":"The energy transferred when 1 mole of a compound is formed from its elements under standard conditions (298K and 100kPa), with all reactants and products in their standard states.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":31,"explanation":null,"deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974846,"front":"How does the ionization energy affect the enthalpy of formation in the Born Haber cycle?","back":"The ionization energy contributes to the enthalpy of formation in the Born Haber cycle by balancing the lattice enthalpy.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":32,"explanation":"The ionization energy is a measure of the energy required to remove an electron from an atom or ion. In the Born Haber cycle, the ionization energy is one of the factors that contribute to the enthalpy of formation. It helps balance the lattice enthalpy, which is the energy released when ions come together to form a solid lattice. By considering the ionization energy, the Born Haber cycle accounts for the energy needed to form ions and the energy released when the lattice is formed.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974847,"front":"Describe the stability of CaCl2 compared to CaCI and CaCI3.","back":"CaCl2 is the most stable form as it has the most exothermic enthalpy of formation compared to CaCI and CaCI3.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":33,"explanation":"CaCl2 is the most stable form because it has the highest exothermic enthalpy of formation. This means that it releases the most energy when it is formed, indicating a more stable compound. In comparison, CaCI and CaCI3 have lower enthalpies of formation, suggesting they are less stable. The higher stability of CaCl2 can be attributed to the balanced charges of the calcium ion and chloride ions in the compound.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974848,"front":"What is a spontaneous process?","back":"A process that proceeds on its own without any external influence.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":34,"explanation":"A spontaneous process occurs without needing external intervention to initiate or sustain it. It happens naturally due to the system's inherent properties and tendencies. This contrasts with non-spontaneous processes that require external energy or work input to occur.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974849,"front":"What is activation energy?","back":"The energy required to start a reaction.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":35,"explanation":"Activation energy is crucial in determining the rate of a chemical reaction. It represents the energy barrier that reactant molecules must overcome to transform into products. Higher activation energy leads to slower reactions, while lower activation energy accelerates the process.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974850,"front":"Describe the relationship between exothermic reactions and thermodynamic stability.","back":"Exothermic reactions result in products that are more thermodynamically stable than the reactants.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":36,"explanation":"Exothermic reactions release energy, indicating a decrease in the system's internal energy. This often leads to the formation of products that are more thermodynamically stable than the reactants, as the excess energy is released to the surroundings, increasing the overall stability of the system.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974851,"front":"What is entropy?","back":"Entropy is a description of the number of ways atoms can share quanta of energy.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":37,"explanation":"Entropy is a measure of the disorder or randomness in a system. It quantifies the distribution of energy among particles in a system, reflecting the number of possible arrangements or configurations the system can have at a microscopic level.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974852,"front":"How does the entropy of substances with more ways of arranging their atoms and energy compare to substances with fewer ways?","back":"Substances with more ways of arranging their atoms and energy have higher entropy.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":38,"explanation":"Substances with more ways of arranging their atoms and energy have higher entropy because entropy is a measure of the number of possible microscopic configurations a system can have. More arrangements mean more disorder and unpredictability, leading to higher entropy.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974853,"front":"What is the relationship between the entropy of solids, liquids, and gases?","back":"Solids have lower entropies than liquids, which are lower than gases.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":39,"explanation":null,"deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974854,"front":"What happens to the entropy of a solid as its temperature increases?","back":"The entropy of a solid increases as its temperature increases.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":40,"explanation":"As the temperature of a solid increases, the thermal vibrations of its atoms or molecules also increase, leading to a greater number of microstates available to the system. This results in an increase in entropy, as there are more ways to arrange the particles at higher temperatures.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}},{"id":974855,"front":"What is the relationship between boiling and entropy?","back":"There is a bigger jump in entropy with boiling than with melting.","front_language":"English","back_language":"English","front_image":"","back_image":"","order":41,"explanation":"Boiling involves a phase transition from liquid to gas, where molecules gain significant freedom of movement, leading to a larger increase in disorder. In contrast, melting, while also a phase change, retains more molecular structure, resulting in a smaller entropy change. This highlights the profound impact of molecular arrangement on entropy.","deleted_at":null,"flashcard_deck_id":"EdJvq","original_id":null,"examMode":{"text":"","correct":"","incorrect":"","info":""}}]

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