Thermodynamics

• The concept of thermal equilibrium allows for the definition of temperature and the study of heat transfer.
• Enthalpy change for the formation of one mole of a compound is formed from its elements in their standard states under standard conditions.
• An example of an enthalpy change for the formation of one mole of a compound is formed from its elements in their standard states under standard conditions is the formation of water.
• Enthalpy change for the formation of water is -239 kJ.
• Enthalpy change of solution is the change in energy when one mole of an ionic substance is dissolved in the minimum amount of solvent to ensure no further enthalpy change is observed upon further dilution.
• Enthalpy change of solution is calculated by knowing the lattice dissociation enthalpy and the enthalpy of hydration.
• The first ionization energy of lithium is required to remove an electron to form lithium plus, which is endothermic.
• One way to form lithium chloride is by elements in their standard states, forming a solid ionic lattice, which is lithium chloride.
• To form ions in the gaseous state, we need to break the bond between chlorine atoms and form a single chlorine acid, which requires energy.
• Theoretical and experimental lattice enthalpies can differ depending on how purely ionic the compound is.
• The next step is to convert lithium solid into lithium gas, which is endothermic.
• The next step in the cycle involves forming magnesium oxide by ionizing magnesium ions and oxide ions.
• Born here is a bit like HESA cycles, with different routes to form the same product.
• Some ionic compounds have a little bit of covalent character.
• The next step is to form lithium chloride by adding an electron to chlorine, which is exothermic.
• The answer should be positive if the reaction is endothermic and negative if the reaction is exothermic.
• An alternative way to form lithium chloride is by forming ions in the gaseous state and then forming lithium chloride.
• Lattice enthalpy is calculated by subtracting the start point from the end point.
• The first electron affinity is exothermic because it involves adding an electron to a neutral atom and forming a negatively charged ion.
• The second electron affinity is endothermic because it involves adding an electron to an ion that is already negatively charged.
• The direction of the reaction is determined by the arrow on the chemical equation.
• The start and end points are determined by the direction of the reaction.
• If Delta H is negative and Delta s is positive, the reaction is feasible at any temperature.
• Endothermic reactions with a negative entropy will never be feasible, regardless of the temperature.
• Exothermic reactions with a positive entropy will always be feasible, regardless of the temperature.
• The decomposition of sodium hydrogen carbonate is an endothermic process that is not a favorable change, but it does occur from a solid to a gas.
• Freezing water is an exothermic process that gives out heat energy when changing from a liquid to a solid, and this process only happens below a certain temperature.
• If Delta G is 0, the reaction is not feasible.
• If Delta H is positive and Delta s is negative, the reaction is not feasible at any temperature.
• Reaction feasibility can be calculated by subtracting a larger number from the enthalpy (ΔH) and entropy (ΔS) parts of the reaction equation.
• The Born-Haber cycle can be used to calculate the first ionization of lithium, which is 5.19.
• The Born-Haber cycle can be used to calculate the enthalpy change of a reaction, regardless of the route taken.
• The lattice enthalpy of formation is the energy required to form a compound from its elements in their standard states.
• Lithium ions exist in the gaseous state, which can be used to form lithium chloride.
• The Born-Haber cycle can be used to calculate the first electron affinity of chlorine, which is -3.64.
• The Born-Haber cycle can be used to calculate the lattice enthalpy of formation of lithium chloride.
• Enthalpically favorable reactions are exothermic ones because the products of a lower energy than the reactants.
• Disorder, or isorder, is a tendency for things to become more disordered over time, as everything tends towards a disorderly fashion because it's lower in energy.
• The enthalpy change of a reaction is independent of the route taken.
• The number of particles and the arrangement of particles both affect change in entropy.