Termodinamica 6

in order to have "ionic equilibria":

• we need to have a strong electrolyte

• we have to ensure that the electro-neutrality is preserved

• we need to have weak electrolyte

• we need to have an ideal system

when we approach ionic equilibria, we usually use the concentration in terms of:

• molar fraction

• weight fraction

• molality

• molarity

what is a buffer solution ?

• an aqueous solution of a weak acid and its coniugate base

• an aqueous solution of a strong acid and its coniugate base

• an aqueous solution of a strong base and its coniugate acid

• none

 $AB\ \leftrightarrow\ A\ +\ B\ \$  what is the correct expression of the overall Gibbs free energy in the case of generic reaction in aqueous solution? (all the G are with a bar on top)

•  $G\ =\ N_sG_s+N_{AB}G_{AB}+N_AG_A+N_BG_B$  

•  $G\ =\ N_sG_s+N_AG_A+N_BG_B$  

•  $G\ =N_{AB}G_{AB}+N_AG_A+N_BG_B$  

•  $G\ =\ N_sG_s+N_{AB}G_{AB}$  

what is a "pseudo-component" ?

• a fake component which is given by overall number of moles of the two ions (comes from the dissociation)

• a component that is teoretically present at equilibrium, but we take it as a reference

• a component that is not present at equilibrium, it appear only when we have full dissociation

• a component that is present only in the case of strong electrolyte

what is the "Debye-Huckel" equation ?

• $\ln\left[\gamma_{\left(+-\right)}^{\nu}\right]=-a\left|Z_+Z_-\right|\ln I$

• $\ln\left[\gamma_{\left(+-\right)}^{ }\right]=\left|Z_+Z_-\right|\ln I$

• $\ln\left[\gamma_{\left(+-\right)}^{\nu}\right]=a\left|Z_+Z_-\right|$

• $\ln\left[\gamma_{\left(+-\right)}^{\nu}\right]=-a\left|Z_+Z_-\right|\ln I+\ln\gamma^{\nu}$

what is the correct expression of the ionic strength ?

•  $\frac{1}{2}\sum_{ }^{ }Z_iC_i^2$  

•  $\frac{1}{2}\sum_{ }^{ }Z_i^2C_i^{ }$  

•  $\sum_{ }^{ }Z_iC_i^2$  

•  $\frac{1}{2}\sum_{ }^{ }Z_iC_i^2+\frac{1}{2}\prod_{ }^{ }x_i\ln\gamma$  

what is the correct definition of "spreading pressure"

• $d\pi=-d\gamma$

• $\pi=\sum_{ }^{ }\gamma_i$

• $d\pi=d\gamma+dP$

• $d\pi=d\gamma-\sum_{ }^{ }\Gamma_id\mu_i$

which one on these equation, is NOT a Gibbs adsorption isotherm ?

•  $d\gamma+\sum_{ }^{ }\Gamma_id\mu_i=0$  

•  $d\pi=RT\sum_{ }^{ }\Gamma_id\ln P+\sum_{ }^{ }\Gamma_id\ln\gamma_i$  

•  $\frac{A}{N^{\sigma}}d\pi=RT\ln P$  

•  $d\pi=\frac{RT}{A}\sum_{ }^{ }\Gamma_id\mu_i+\ln P$  

which one of these equation, describe the Langmiur model

• $\frac{P}{K+P}$

• $\frac{\ln P}{\ln P+K}$

• $\frac{K+P}{K}$

• $\frac{K\left(P-1\right)}{K}\$