I need Part C ONLY 5. You have 1 L of a solution containing 0.025 M of both Sr^+

Question

I need Part C ONLY 5. You have 1 L of a solution containing 0.025 M of both Sr^+2 and Ca^+2 ions. You slowly add Na2C2O4. a. Which precipitates first, CaC2O4 or SrC2O4? Why? At what C2O4^-2 concentration does this molecule precipitate? What mass of Na2C2O4? (5 points) (Ans. 1.6x10^-7 M; 2.1x10^-5 g) b. At what C2O4^-2 concentration does the second species, CaC2O4 or SrC2O4, precipitate? (10 points) (Ans. 1.6x10^-5 M) c. What is the concentration of the first ion to precipitate, Sr^+2 or Ca^+2, when the second precipitates? (10 points) (Ans. 2.5x10^-4 M)

Explanation / Answer

5.

Ksp values for CaC2O4 = 4.0 x10^-9

When the second ion precipitates, [C2O4^2-] = 1.6 x 10^-5 M

Ksp = [Ca^2+][C2O4^2-]

[4.0 x10^-9] = [Ca^2+] [1.6 x 10^-5]

[Ca^2+] = [4.0 x10^-9] / [1.6 x 10^-5]

[Ca^2+] = 2.5 x 10^-4 M

SrC2O4 = 5 x10^-8

----------------------

a.

As the Ksp value of CaC2O4 is smaller than SrC2O4. Hence, CaC2O4 precipitates first.

Ksp = [Ca^2+][C2O4^2-]

2.3 x10^-9 = [0.025] [C2O4^2-]

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.