-4 What A chemistry graduate student is given 100. mL of a 1.10 M trimethylamine ((CH,) N) solution. Trimethylamine is a weak base with K, = 7.4 x 10 mass of (CH, NHB1 should the student dissolve in the (CH, N solution to turn it into a buffer with pH = 10.56? You may assume that the volume of the solution doesn't change when the (CH, NHB is dissolved in it. Be sure your answer has a unit symbol, and round it to 2 significant digits.

What are the factors that affect buffer capacity? Explain in 2-3 sentences.

Before (mol) Change (mol) After (mol) ap here or pull up for additional resources A student was titrating a solution of HC₂H₂O₂ with a Sr(OH)₂ solution. Determine the pH at a particular point in the titration. Do this by constructing a BCA table and determining the pH. The value of Ka for HC₂H₂O₂ is 1.5 x 10%. Complete Parts 1-2 before submitting your answer. NEXT 40.0 mL of a 0.200 M HC₂H₂O₂ solution was titrated with 100.0 mL of 0.100 M Sr(OH)2 (a strong base). Fill in the ICE table with the appropriate value for each involved species to determine the moles of reactant and product after the reaction of the acid and base. You can ignore the amount of water in the reaction. HC,H,Oz(aq) 1.00 x 10² 0 -1.00 x 10-² + Question 7 of 8 0.100 1.20 x 10² OH(aq) 0.200 -1.20 x 10" 2.00 x 10-³ 2.00 x 10-² 2 -2.00 x 10" -2.00 x 10-² H₂O(l) 8.00 x 10" RESET -8.00 x 10" C,H,Or(aq) Sub

A chemistry graduate student is given 100. mL of a 1.80M trimethylamine ((CH N solution. Trimethylamine is a weak base with K,=7.4 x 10 *. What (CH3), NHC1 should the student dissolve in the (CH3),N solution to turn it into a buffer with pH =10.99? mass of You may assume that the volume of the solution doesn't change when the (CH, NHCI is dissolved in it. Be sure your answer has a unit symbol, and round it to 2 significant digits.

How can we solve questions 3 and 4? Calculate the pH of a 0.350 M solution of potassium phenolate, KC6H5O. Ka for phenol (CH5OH) is 1.0 x 10-10. How do the concentration/volumes of the buffer affect the buffer capacity? E.g., 50.0 mL of 0.10 M acetic acid solution with 50.0 mL of 0.10 M sodium acetate solution vs. the buffer you made in the lab (25.0 mL of 0.10 M acetic acid solution with 25.0 mL of 0.10 M sodium acetate solution).

Answer using this data for the remaining questions on this page: For 1.0L of an acetic acid solution: Ka = 1.8 x 10-5 and [HA] = 0.250M 2. Calculate the pH of the solution. 3. What is the pka? 4. Calculate the pH of the solution if you make it a buffer by adding enough solid sodium acetate to make the concentration of acetate ion equal to 0.35M. The volume of the solution does not change. 5. What is the new concentration of [HA] if 2.0mL of 5.00M of HCI is added to 1.000L of the solution above? 6. What is the new pH?

4. What is the pH at each of the following points in the titration of 25.00 mL of 0.100 M CH,CH;COOH with 0.100 M NaOH? a) before the addition of any NaOH; b) after the addition of 10.00 mL of 0.100 M NaOH; c) after the addition of 12.50 mL of 0.100 M NaOH; d) after the addition of 25.00 mL of 0.100 M NaOH; e) after the addition of 26.00 mL of 0.100 M NaOH.

Q:3-3 Consider a 1.00 L buffer made by adding 0.140 mol cyanic acid HCNO, and 0.110 mol potassium cyanate ,KCNO, to sufficient water. Calculate the pH a buffer (a) Before any acid or base is added; (b) after the addition of 0.015 mol of HNO3; (c) After the addition of 0.015 mol of KOH. In parts (b) and (c) assume the volume does not change . pka(HCNO)=3.48; ka(HCNO)= 3.3 X 104.

At pH 10.0, only 0.019 g of MgCl2 will dissolve per 1 L of solution. What is the Ksp of magnesium hydroxide, Mg(OH)2?