Term
| in weak electrolytes, there is an equilibrium between __ and __ |
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Definition
partially dissociated molecules
ions |
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Term
| Is pure water an electrolyte solution? |
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Definition
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Term
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Definition
| (mol solute)/(kg solvent) |
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Term
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Definition
| (mol solute)/(mol solvent) |
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Term
| can molality be defined for a solvent? |
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Definition
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Term
| can molarity be defined for a solvent? |
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Definition
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Term
| what is the molarity of water? |
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Definition
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Term
| for equilibrium electrochemistry, should you use molality or molarity? |
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Definition
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Term
| at ambient conditions, how are molarity (c) and molality (b) related? |
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Definition
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Term
which of the following depend on T and P?
molality, molarity, mole fraction, mass fraction, volume fraction, percent |
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Definition
| molarity and volume fraction |
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Term
| what is the equation for chemical potential for an ideal solution? |
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Definition
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Term
| for the chemical potential eqn, do the terms depend on concentration? |
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Definition
standard state term: no
log term: yes |
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Term
| for the chemical potential eqn, do the terms depend on the concentration scale? |
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Definition
standard state term: yes
log term: yes |
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Term
| does the chemical potential depend on the concentration scale? |
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Definition
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Term
| the chemical potential is a function of __, __, and __ |
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Definition
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Term
| for electrolyte solutions, molality should be used in all cases, except __ and __ |
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Definition
electrolyte conductivity
electrochemical kinetics |
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Term
| μ^(o,x) is standard chemical potential on the __ concentration scale |
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Definition
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Term
| μ^(o,b) is standard chemical potential on the __ concentration scale |
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Definition
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Term
| what is the relationship between molar fraction (x) and molality (b)? |
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Definition
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Term
| define chemical potential, μ |
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Definition
| a form of potential energy that can be absorbed or released during a chemical reaction |
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Term
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Definition
| effective concentration of a solute for the purposes of mass action |
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Term
| define activity coefficient, γ |
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Definition
| a factor used in thermodynamics to account for deviations from ideal behavior in a mixture of chemical substances |
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Term
| what is the relationship between γ^x and γ^b? |
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Definition
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Term
| what is the unit of chemical potential? |
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Definition
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Term
| what are the units of activity and activity coefficient? |
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Definition
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Term
| for a dilute electrolyte solution, x and γ^x of water are close to __ |
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Definition
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Term
| For a dilute electrolyte solution, chemical potential μ of water is close to __. Why? |
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Definition
standard chemical potential (μ^o) of water
because x and γ^x are close to 1 |
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Term
| for electrolyte solutions, μ is a sum of what contributions? |
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Definition
the anion and cation contributions
μ = (ν^+)(μ^+) + (ν^-)(μ^-) |
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Term
| when I -> 0,
ab -> ? and γb -> ? |
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Definition
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Term
| what is the physical meaning of the activity coeff.? |
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Definition
| it shows the difference between the chemical potential of the ith species in real vs. ideal solutions |
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Term
| can the activity coeff. of an ion be experimentally measured? |
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Definition
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Term
| can the activity coeff. of an ion be theoretically calculated? |
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Definition
| yes, for a dilute solution |
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Term
| can the activity coeff. of an electrolyte be experimentally measured? |
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Definition
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Term
| for a strong electrolyte, how is the mean activity coeff. γ related to the anion and cation activity coeff's γ- and γ+? |
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Definition
it is approximately equal to both
(γ = γ- = γ+) |
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Term
| the activity coefficient of the anion and cation are usually __ |
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Definition
different
(only approx. equal for a strong electrolyte) |
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Term
| are the absolute values of standard chemical potentials known? |
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Definition
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Term
| Gibbs energy of formation can be found __ |
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Definition
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Term
| Debye-Huckel theory provides a method to calculate what? |
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Definition
| the activity coefficient of a single ion surrounded by an ionic atmosphere |
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Term
| does the mean activity coeff. depend on concentration? |
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Definition
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Term
| at high concentrations, the mean activity coeff. can be __ |
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Definition
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Term
| the total concentration of a weak electrolyte is a sum of what? |
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Definition
the concentration of the dissociated ions and
the concentration of the undissociated molecules |
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Term
| what is the equation for pH? |
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Definition
pH = -log[H+]
or [H+] = 10^(-pH) |
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Term
| what is the activity of water in pure water? |
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Definition
1
but it can deviate in highly concentrated solutions |
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Term
| at 25 C and 1 bar, what is the pH of pure water? |
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Definition
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Term
| pH is hard to define in what kind of solutions? |
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Definition
| highly concentrated solutions |
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Term
| what are the 2 main problems in defining pH? |
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Definition
1. pH is a thermodynamic characteristic of an individual ion, so assumptions must be made to find it
2. commercially available pH probes are not usable in all environments |
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Term
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Definition
| solution made of a weak acid and salt or a weak base and salt, which resists changing pH upon small additions of acid or base |
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