Question

A chemist fills a reaction vessel with 0.534 g silver chromate Ag2CrO4 solid, 0.191 M silver Ag+ aqueous solution, and 0.823 M chromate CrO4−2 aqueous solution at a temperature of 25.0°C. Under these conditions, calculate the reaction free energy ΔG for the following chemical reaction: Ag2CrO4s +2Ag+aqCrO4−2aq Use the thermodynamic information in the ALEKS Data tab. Round your answer to the nearest kilojoule.

Answer 1

`\large \boxed{\Delta G = \text{60 kJ}}`

Step-by-step explanation:

Ag₂CrO₄ ⇌ 2Ag⁺ + CrO₄²⁻; Ksp = 1.12× 10⁻¹²

I/mol·L⁻¹: 0.191 0.823

To get ΔG under these conditions, we can use the equation

ΔG = ΔG° + RTlnQ = -RTlnK + RTlnQ = RTln[Q/K]

1. Calculate Q

`Q =\text{[Ag$^(+)$]$^(2)$[Cr$_(2)$O$_(4)^(2-)$]} = 0.191^(2)*0.823 = 0.03002`

2. Calculate ΔG

T = (25.0 + 273.15) K = 298.15 K

`\begin{array}{rcl}\Delta G& =& RT \ln \left ((Q)/(K) \right )\\\\&=& 8.314 * 298.15 * \ln\left ((0.03002)/(1.12 * 10^(-12)) \right )\\\\&=& 2479 * \ln(2.860 *10^(10))\\&=& 2479 * 24.01\\& = & \text{59520 J}\\& = & \textbf{60 kJ} \\\end{array}\\\large \boxed{\mathbf{\Delta G} = \textbf{60 kJ}}`