Using the following data, quantify your answers to problem...

Using the following data, quantify your answers to problem $17.22 . S^{\circ}(298 \mathrm{K}) / \mathrm{J} \mathrm{K}^{-1} \mathrm{mol}^{-1}: \mathrm{Na}(\mathrm{s}), 5.3$ $\mathrm{Na}(\mathrm{g}), 153.7 ; \mathrm{Cl}(\mathrm{g}), 165.2 ; \mathrm{Cl}_{2}(\mathrm{g}), 223.0 ; \mathrm{O}_{2}(\mathrm{g})$ $205.1 ; \mathrm{CO}(\mathrm{g}), 197.7 ; \mathrm{CO}_{2}(\mathrm{g}), 213.8$.

Using the following data, quantify your answers to problem $17.22 . S^{\circ}(298 \mathrm{K}) / \mathrm{J} \mathrm{K}^{-1} \mathrm{mol}^{-1}: \mathrm{Na}(\mathrm{s}), 5.3$
$\mathrm{Na}(\mathrm{g}), 153.7 ; \mathrm{Cl}(\mathrm{g}), 165.2 ; \mathrm{Cl}_{2}(\mathrm{g}), 223.0 ; \mathrm{O}_{2}(\mathrm{g})$
$205.1 ; \mathrm{CO}(\mathrm{g}), 197.7 ; \mathrm{CO}_{2}(\mathrm{g}), 213.8$.

Key Concepts

Standard Molar Entropy

Standard molar entropy is a thermodynamic quantity representing the inherent randomness or disorder of a substance per mole at a defined standard state, typically at 298 K and 1 atm pressure. It provides a basis for calculating changes in disorder during chemical reactions and phase transitions, and is expressed in units of joules per kelvin per mole (J·K?¹·mol?¹).

Reaction Entropy Change

The entropy change of a reaction (?S°) is determined by calculating the difference between the sum of the standard molar entropies of the products and that of the reactants, each multiplied by their respective stoichiometric coefficients. This concept is essential in predicting the spontaneity and feasibility of chemical reactions.

Standard Thermodynamic Data

Standard thermodynamic data, such as standard molar entropy values, are essential for quantifying the energetics of chemical reactions. Such data are measured under consistent conditions (standard state: 298 K, 1 atm) and allow for accurate calculations of thermodynamic functions, providing a reference point for comparing changes among different substances.

Stoichiometry in Thermodynamic Calculations

Stoichiometry in thermodynamic calculations involves using the balanced chemical equation to appropriately weight the contribution of each species when determining overall reaction parameters like entropy change. This ensures that the calculated properties reflect the true stoichiometric relationships in the reaction system.

Transcript

00:01 Okay, so to answer this problem it is useful to think of the overall reaction that's given as the result of a series of steps that need to occur for that reaction to happen.

00:13 If we know the energies required for each of those steps, all we need to do is add them up to get the final reaction enthalpy.

00:22 So let's look at different steps that we need to perform for that reaction to happen.

00:27 We start with the potassium in solid state.

00:30 The first thing that we need to do is take that potassium from a solid state to a gas state because it needs to react with the chlorine that's also in the gas phase.

00:38 They both need to be in the same phase for them to react.

00:42 This reaction is basically a sublimation reaction and we are given the enthalpy of sublimation for potassium which is 64 kilojoules per mole.

00:53 So that would be the energy required to fulfill the first step.

00:58 Let's look at the second step.

00:59 In the second step we're going to take that gas, the potassium in gas form and ionize it.

01:06 Why do we want to ionize it? because the final product is an ionic salt.

01:10 So we need the ion there to bond with the negative chlorine anion and form the solid.

01:17 So we need to ionize the potassium and that is essentially the ionization energy for potassium that's also given and it's 419 kilojoules per mole.

01:28 The third step is now we're going to look at the chlorine gas...

Please give Ace some feedback