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 is 75.0%.

the answer is b because, investigating whether another species of moth also drinks tears might be interesting, but it would not directly explain why this species of moth does.

to explain why this species of moth drinks tears, the scientist could ask: "what nutrients that moths need are in elephant tears? "

the scientist could experiment with moth repellent or oter ways to keep the moths away, but that would not answer his original question.