Question

i need help with part c) please. please show me your work

3:51 PM Tue Oct 29 chem 315 Insert Draw View Home -- Insert Space A Text Mode Lasso Select Pg 1 of 6 Chemistry 315 Unit 2B1 4. A 25.00 mL solution containing 0/03110 M Na2C2O4 was titrated with 0.02570 M Ca(NO3)2 to precipitate calcium oxalate: Ca2+ + C2042 → CaC204 (s). Find pCa2+ at the following volumes of Ca(NO3)2. Ksp for CaC2O4 = 1.3 x 10- a) 10.00 mL ANSWER = pCa2+ = 6.06 b) Vea ANSWER = pCa2+ = 3.94 c) 35.00 mL ANSWER = pCa2+ = 2.69 Recommended Harris problems: Ch. 15: 3 (only calculate (Ag*]), 5 (only calculate (Ag*])

Answer 1

page-01 Answers (©) when 35 ml. d 0.02570 M CalNog), added 2- 25.00 ml Solution contains = 0.03110M (N9, 9204) it is breated with Ca(NO3)2 = 0.02570 M given geaction : Calt +6,042-cac204 (5) after equivalence point, there is excess of ca²+ aons moles of cazt = added moles de capta moles of czby added (0.0254) (0.02570 molle) -(0.025%)(0,03107 = 0.0008995 mol -0.0007775 med. =1.22x10-4 moles of cakt = 0.000122 mol volume of solution after addition 85 ml of 0.02570 M Ca (NO), (0.025 +0.035) = 0.06

page-02 [cast] = 0.000192 met 0.06L = 2.033 X 107 = 0.002033 M p Ca²+ = -log[cat] = -log (0.002033] = 2.6918 1pcal+ = 2.69