Answer:
Kc ≅ 100 (1 sig. fig.)
Step-by-step explanation:
2NH₃(g) ⇄ N₂(g) + 3H₂(g)
C(i) 3.00 mol/L 0 0
ΔC -2x +x +3x
C(eq) 0.600 mol/L x 3x
3.00 - 2x = 0.600 => x = 3.00 - 0.600/2 = 1.2 mole/L
At equilibrium Kc = [N₂][H₂]³/[NH₃]² = (x)(3x)³/(3·1.2)² = (1.2)(3.6)³/(0.600)² = 155.52 (calculator)
Rounds to 1 sig. fig. based on given 3.00 moles NH₃(g)' Kc ≅ 100.