Question

Write its reaction quotient, Qc. (Omit states-of-matter in your answer.) (the following are examples of heterogeneous equilibria):

a) 2Na2O2(s) + 2CO2(g) ⇌ 2Na2CO3(s) + O2(g)
b) H2O(l) ⇌ H2O(g)
c) NH4Cl(s) ⇌ NH3(g) + HCl(g)

The answers I have already tried (These answers are already wrong):
a) Q_{c} = [Na_2CO_3]^2[O_2] /[Na_2O_2]^2[CO_2]^2
b) Q_{c} = [H_2O] /[H_2O] ---because it contains too many substances
c) Q_{c} = [NH_3][HCl] /[NH_4Cl] ---because it contains too many substances

Answer 1

The reaction quotient (Qc) is a measure used to determine the progress of a chemical reaction towards equilibrium. It is calculated using the concentrations or pressures of gaseous or dissolved species in the reaction. Expressions for Qc vary based on the stoichiometry of the specific reactions involved.

Step-by-step explanation:

The reaction quotient (Qc) is a measure used to determine how far a reaction has proceeded towards equilibrium and in which direction it must proceed to reach equilibrium. For a set of reactions, the expressions can be written as follows:

• 
  For reaction (a) N2(g) + 3H2(g) ⇒ 2NH3(g), the Qc expression is:
  Qc = [NH3]2 / ([N2] · [H2]3)
  
• 
  For reaction (b) 4NH3(g) + 5O2(g) = 4NO(g) + 6H2O(g), the Qc expression is:
  Qc = ([NO]4 · [H2O]6) / ([NH3]4 · [O2]5)
  
• 
  For reaction (c) N2O4(g) = 2NO2(g), the Qc expression is:
  Qc = [NO2]2 / [N2O4]
  

These expressions include only the concentrations or pressures of the species in the gaseous or solute state since solids and liquids are omitted from the reaction quotient calculation.