You may want to reference (A pages 579 - 587) Section 14.8 while completing this

Question

You may want to reference (A pages 579 - 587) Section 14.8 while completing this problem. The following reaction 2H_2 S(g) 2H_2 (g) + S_2 (g), K_c = 1.67 Times 10^-7 at 800 degree C is carried out with the following initial concentrations: [H_2 S] = 0.300 M, [H_2] =0.225 M, and [S_2] = 0.00 M. Find the equilibrium concentration of [S_2]. Express your answer to three significant figures and include the appropriate units. Consider the reaction of A to form B: 2A (g) B(g) K_c = 1.4 Times 10^-5 (at 298 K) A reaction mixture at 298 K initially contains [A] =0.30 M What is the concentration of B when the reaction reaches equilibrium? Express your answer to two significant figures and include the appropriate units.

Explanation / Answer

Kc = [H2]2[S2] /[H2S]2

1.67*10-7 = (0.225+2x)2(x)/(0.300-2x)2

As Kc is very small, we can assume (0.300-2x) = 0.300 and (0.225+2x) = 0.225

1.67*10-7 = ((0.225)2(x)/(0.300)2

x = 1.67*10-7 (0.300)2 / (0.225)2

= 2.97 * 10-7

[S2] at equilibrium = 2.97 * 10-7 M

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

Kc = [B]/[A]2

1.4*10-5 = x/(0.30-2x)2

As Kc is low, we can assume (0.30-2x) = 0.30

1.4*10-5 = x/(0.30)2

x = 1.4*10-5 (0.30)2

=1.26*10-6

[B] = 1.26*10-6 M

2H2S (g) 2H2 (g) S2 (g) Initial 0.300 0.225 0.00 Change -2x +2x +x Equilibrium (0.300-2x) (0.225+2x) x

Related Questions

Navigate

• Browse (All)
• Browse Y
• Subjects

---

---

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