NT-1 Given: 7.70x10^-5 g of acetic acid (CH₃COOH or, HAc) are placed in a beaker. Pure water is added until solution volume is 8.00 liters. Temperature is 50 C. Calculate the following quantities to a precision level of three significant figures. Hint: This is a weak acid at a low concentration; therefore, do not assume that the proton concentration is equal to the acid total concentration (because it is not). Find:

1. Precise pH of the solution. Ignore temperature corrections for this part of the problem, but add the following note to your solution temperature corrections to dissociation constant values have not been made.
2. Molar concentration of dissociated acetate (acetate ion) in solution (mol Ac^-/L)
3. Mass concentration of dissociated acetate (acetate ion) in solution in micrograms per liter (ug Ac^-/L) where Ac = CH₃COO^-
4. Mass fraction of dissociated acetate ion in the solution (g Ac^-/g Solution)
5. Parts per billion dissociated acetate ion by mass (ppb_m Ac). Is it the same number as for ug/L mass concentration? Why?
6. Normal concentration of the acid, HAc (eq H⁺/L)
7. Mass concentration of the acid, HAc as CaCO₃ (mg HAc /L as CaCO₃)

HINT: Because HAc is a weak acid (pK > 2) only a portion of the protons will dissociate from Ac. To start,

1. a) Calculate [H⁺] from the monoprotic acid eqn. in the CE 142 Acid-Base lecture.; b) Calculate pH.
2. Use [H⁺] to calculate a₁ (Eqn: 4-47 in your book), the fraction of total acid that dissociated.
3. Molar conc. of Ac^-, [Ac^-] = a₁A_T where A_T is the molar conc. of total acid in solution.