Question

Consider the following reaction at 25 °C: Ba(OH)₂･8 H₂O(s) + 2 NH₄Cl(s) → BaCl₂(s) + 2 NH₃(g) + 10 H₂O(l) If ∆G° = -14.1 kJ/mol, determine the value of ∆G assuming that a mixture contains 12.0 g of Ba(OH)₂･8H₂O, 4.00 g of NH₄Cl(s), 7.79 g of BaCl₂, 1.83 atm of NH₃ and 6.73 g of H₂O.

Answer 1

To determine the value of ∆G for the given reaction, we need to calculate the values of the reactants and products and use the equation ∆G = ∆G° + RTlnQ.

Step-by-step explanation:

To determine the value of ∆G for the given reaction, we can use the equation ∆G = ∆G° + RTlnQ, where ∆G° is the standard Gibbs free energy change, R is the gas constant, T is the temperature in Kelvin, and Q is the reaction quotient.

First, we need to calculate the values of the reactants and products:

• Ba(OH)₂･8 H₂O: molar mass = 315.45 g/mol, moles = mass/molar mass
• NH₄Cl: molar mass = 53.49 g/mol, moles = mass/molar mass
• BaCl₂: molar mass = 208.23 g/mol, moles = mass/molar mass
• NH₃: pressure = 1.83 atm, V = 1 L, n = PV/RT
• H₂O: molar mass = 18.02 g/mol, moles = mass/molar mass

Based on these calculations, we can substitute the values into the equation and solve for ∆G.

Answer 2

To calculate the Gibbs free energy (ΔG) for the given reaction under non-standard conditions, one must apply the Gibbs free energy equation using the provided data for the substances involved, including the partial pressure of NH₃ for the reaction quotient (Q).

Step-by-step explanation:

The student asks how to calculate the Gibbs free energy (ΔG) of a reaction under non-standard conditions, given the reaction at 25 °C for the chemical equation Ba(OH)₂･8 H₂O(s) + 2 NH₄Cl(s) → BaCl₂(s) + 2 NH₃(g) + 10 H₂O(l) with ΔG° = -14.1 kJ/mol. To determine the value of ΔG under the given conditions, one must use the Gibbs free energy equation: ΔG = ΔG° + RTlnQ, where ΔG° is the standard Gibbs free energy change, R is the universal gas constant, T is the temperature in Kelvin, and Q is the reaction quotient reflecting the actual partial pressures and concentrations of reactants and products.

However, the student should be reminded that this equation applies to gases and solutions, and since all substances except NH₃ are either solids or liquids, only the partial pressure of NH₃ will be considered in the Q value. Calculations involving changes in mole amounts of reactants and products are necessary to determine the reaction quotient (Q) and subsequently find ΔG using the Gibbs free energy equation.