In the text the equation δg = δg° + rt ln(q) was derived for gaseous reactions where the quantities in q were expressed in units of pressure. we also can use units of mol/l for the quantities in q—specifically for aqueous reactions. with this in mind, consider the reaction hf(aq) equilibrium reaction arrow h +(aq) + f −(aq) for which ka = 7.2 ✕ 10−4 at 25°c. calculate δg for the reaction under the following conditions at 25°c. based on the calculated δg values, in what direction will the reaction shift to reach equilibrium for each of the five sets of conditions?

ΔGrxn(25°C) = 2113.839 KJ/mol

⇒ ΔG >> 0 and K << 1; then the reaction shift to the left to reach equilibrium

Explanation:

∴ in the equilibrium: Q = Ka = 7.2 E-4 (25°C)

∴ ΔG°HF(aq)(25°C) = - 294.595 KJ/mol

∴ R = 8.3145 E-3 KJ/mol.K

∴ T = 25°C = 298.15 K

⇒ ΔGrxn(25°C) = {-294.595 KJ/mol + [(8.3145 E-3 KJ/.K.mol)*(298.15K)]} Ln(7.2 E-4)

⇒ ΔGrxn(25°C) = [ -295.595 KJ/mol + 2.4789 KJ/mol ] * (-7.2363)

⇒ ΔGrxn(25°C) = ( -292.116 KJ/mol ) * ( - 7.2363 )

⇒ ΔGrxn(25°C) = 2113.839 KJ/mol

∴ ΔG >> 0 and K << 1; then the reaction shift to the left to reach equilibrium

the answer to your question is c

when the volume of gas is   changed from   717.73 ml   to 852 ml   the temperature will   change   from 315   c to 452   c

    calculation

this is calculated using the charles law formula

that is,   v1/t1 = v2/t2

          v1=?

        t1 = 315 c   into   kelvin = 315 +273 = 588 k

        v2 = 852   ml

        t2 = 425c + 273 =698 k

make v1   the subject of the formula ( by   multiplying both side by t1)

  v1=( v2 xt1) / t2

v1= (852 ml   x 588 k)/ 698 k= 717.73 ml