1) Reaction
<span>NH4Cl(s) ---> NH3(g) + HCl(g)
2) equilibrium equation, Kc
Kc = [NH3] * [HCl]
3) Table of equilibrium formation
step concentrations
</span>
<span> NH4Cl(s) NH3(g) HCl(g)
start 1.000 mole 0 0
react - x
produce +x + x
------------------ ---------- -----------
end 1 - x +x +x
1 - x = 0.3 => x = 1 - 0.3 = 0.7
[NH3] = [HCl] = 0.7/0.5 liter = 1.4 (I used 0.500 dm^3 = 0.5 liter)
4) Equilibrium equation:
Kc = [NH3] [HCl] = (1.4)^2 = 1.96
Which is the number that you were looking for.
Answer: Kc = 1.96
</span>
Answer: 4 A1+3 02 → 2 Al2O3
Explanation: Two different atoms combines together to produce a compound.