How many moles of sodium hydroxide would have to be added to 225 mL of a 0.377 M acetic acid solution, in order to prepare a buffer with a pH of 4.670?

0.0385 moles of NaOH

Explanation:

One of the way to make a buffer is to combine a weak base with a strong acid. For this case, we have:

CH₃COOH → CH₃COO⁻  +  H⁺

NaOH →  Na⁺  + OH⁻

As every weak acid, we have the equilibrium:

CH₃COOH  +  H₂O  ⇄  CH₃COO⁻  +  H⁺

For this buffer we should know that:

mmoles CH₃COO⁻ at the end = mmoles NaOH.    In conclusion:

mmoles CH₃COO⁻ at the end = mmmoles of CH₃COOH - mmoles of base, we added.

mmoles of  acetic → 0.377 M = mmoles / 225mL ⇒ 84.8 mmmoles

(0.377 M . 225 mL)

Now we can apply the Henderson Hasselbach:

pH = pKa + log (mmmoles NaOH / mmoles of acetic acid - mmoles NaOH)

pKa of acetic → 4.75

4.670 = 4.75 + log ( x / 84.8 - x)

-0.08 = log ( x / 84.8 - x)

10⁻⁰'⁰⁸ = x / 84.8 - x

0.831 (84.8 - x) = x

70.5 - 0.831x = x

70.5 = 1.831x

x = 70.5 mmmoles / 1.831 = 38.5 mmmoles of NaOH

1.consider the following balanced equation and answer parts a through. show calculations for each part.  

3 ag(s) + 4 hno3(aq) → 3 agno3(aq) + no(g) + 2 h2o(l)  

a. calculate the number of moles of agno3 produced by the reaction of 3 moles of ag with excess hno3. if the number to the left of the compound represents the number of moles of the compound which are present, then 3 moles of ag react with 4 moles hno3 to produce 3 moles agno3 (aq).

so the answer to a would be 3 moles.

b. calculate the number of moles of agno3 produced by the reaction of 108 grams of ag with excess hno3.  

i'm not sure how to plug in the grams of silver into an equation using moles to find how many moles are produced.

c. calculate the number of grams of agno3 produced by the reaction of 108 grams of ag with excess hno3  

d. calculate the number of moles of no produced as a byproduct of the reaction of 108 grams of ag with excess hno3.  

e. calculate the number of grams of no produced as a byproduct starting with 108 grams of ag and excess hno3.  

explanation:

the mantle

explanation:

earth is divided into three layers: the crust or the outermost layer on which we live; the underlying, middle layer - the mantle - and the core (the innermost layer of earth).