Question

What is a homogeneous equilibrium system? Give an example of a homogeneous equilibrium reaction. What is a heterogeneous equilibrium system? Write two chemical equations that represent heterogeneous equilibria.

Short answer

A homogeneous equilibrium system is a chemical system where all reactants and products are in the same phase, such as the reaction between nitrogen gas and hydrogen gas to form ammonia gas: \(N_2(g) + 3H_2(g) \rightleftharpoons 2NH_3(g)\). A heterogeneous equilibrium system involves reactants and products in different phases, like the reaction between calcium carbonate (solid) and heat: \(CaCO_3(s) \rightleftharpoons CaO(s) + CO_2(g)\), or the reaction between water (liquid) and carbon dioxide (gaseous) to form carbonic acid (aqueous): \(CO_2(g) + H_2O(l) \rightleftharpoons H_2CO_3(aq)\).

Step-by-step solution

Homogeneous Equilibrium System

A homogeneous equilibrium system is a chemical system in which all the reactants and products are present in the same phase (solid, liquid or gas). That is, all components exist in a single, homogenous mixture.

Example of a Homogeneous Equilibrium Reaction

An example of a homogeneous equilibrium reaction is the reaction between nitrogen gas and hydrogen gas to form ammonia gas: \[N_2(g) + 3H_2(g) \rightleftharpoons 2NH_3(g)\] In this reaction, all the reactants and products are in the gaseous phase.

Heterogeneous Equilibrium System

A heterogeneous equilibrium system is a chemical system in which the reactants and products are present in different phases (solid, liquid, or gas). In other words, the components in a heterogeneous equilibrium system coexist in separate, distinct phases.

Chemical Equations Representing Heterogeneous Equilibria (1)

One example of a heterogeneous equilibrium system is the reaction between calcium carbonate (solid) and heat, which results in calcium oxide (solid) and carbon dioxide (gaseous): \[CaCO_3(s) \rightleftharpoons CaO(s) + CO_2(g)\] In this reaction, we have a solid reactant converting into a solid product and a gaseous product.

Chemical Equations Representing Heterogeneous Equilibria (2)

Another example of a heterogeneous equilibrium system is the reaction between water (liquid) and carbon dioxide (gaseous), which forms carbonic acid (aqueous): \[CO_2(g) + H_2O(l) \rightleftharpoons H_2CO_3(aq)\] Here, we have a gaseous reactant and a liquid reactant combining to form an aqueous product. This is also a heterogeneous equilibrium system, as the reactants and product exist in different phases.