The value of Kc for the thermal decomposition of H₂S is 2.2 x 10⁻⁴ at 1400 K:
2 H₂S(g) ↔ 2 H₂(g) + S₂(g)
initial 3.5 M 0 0
at equilibrium 3.5 M - 2x 2x x
Kc = [S₂][H₂]² / [H₂S]²
2.2 X 10⁻⁴ = x(2x)² / (3.5 - 2x)²
2.2 x 10⁻⁴ = 4 x³ / (3.5)² Assuming x <<<<< 3.5
x = 0.088
Thus [H₂S] = 3.324 M
hey there!:
H2S(aq) <=> H⁺(aq) + HS⁻(aq)
K'c = [H⁺][HS⁻]/[H₂S] = 9.5*10⁻⁸
HS⁻(aq) <=> H⁺(aq) + S²⁻(aq)
K"c = [H⁺][S²⁻]/[HS⁻] = 1.0*10⁻¹⁹
H₂S(aq) <=> 2 H⁺(aq) + S²⁻(aq)
Kc = [H⁺]²[S²⁻] / [H₂S]
= [H+][HS⁻] / [H₂S] * [H⁺][S²⁻]/[HS⁻]
= K'c *K"c
= ( 9.5*10⁻⁸ ) * ( 1.0 x 10⁻¹⁹ )
= 9.5*10⁻²⁷
Hope this helps!
1) T<span>he dissolution of the salt potassium sulfite:
K</span>₂SO₃(aq) → 2K⁺(aq) + SO₃²⁻(aq).
Potassium has +1 charge because it lost one electron to accomplish stabile electron configuration of noble gas argon.
2) From dissolution reaction: n(K⁺) : n(SO₃²⁻) = 2 : 1.
n(K⁺) = 0.700 mol.
0.700 mol : n(SO₃²⁻) = 2 : 1.
n(SO₃²⁻) = 0.700 mol ÷ 2.
n(SO₃²⁻) = 0.350 mol; amount of sulfite anions.
