For each of the following equilibria, write the equilibrium constant expression for Kc. (a) 2 C2H4(g) + O2(g) ⇌ 2 CH3CHO(g) (b) CO(g) + H2O(g) ⇌ CO2(g) + H2(g) (c) 4 NH3(g) + 5 O2(g) ⇌ 4 NO(g) + 6 H2O(g)

Name: Chemistry
Author: McMurry
ISBN: 9781292336145

검증된 단계별 안내

Step 1: Understand that the equilibrium constant expression, Kc, is written as the ratio of the concentrations of the products to the concentrations of the reactants, each raised to the power of their respective coefficients in the balanced chemical equation.

Step 2: For reaction (a) 2 C2H4(g) + O2(g) ⇌ 2 CH3CHO(g), write the Kc expression as: Kc = [CH3CHO]^2 / ([C2H4]^2 * [O2]).

Step 3: For reaction (b) CO(g) + H2O(g) ⇌ CO2(g) + H2(g), write the Kc expression as: Kc = [CO2][H2] / ([CO][H2O]).

Step 4: For reaction (c) 4 NH3(g) + 5 O2(g) ⇌ 4 NO(g) + 6 H2O(g), write the Kc expression as: Kc = [NO]^4 * [H2O]^6 / ([NH3]^4 * [O2]^5).

Step 5: Remember that the concentrations are typically expressed in molarity (moles per liter) and that the equilibrium constant is dimensionless.

주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Equilibrium Constant (Kc)

The equilibrium constant, Kc, is a numerical value that expresses the ratio of the concentrations of products to the concentrations of reactants at equilibrium for a given chemical reaction. It is calculated using the formula Kc = [products]^[coefficients] / [reactants]^[coefficients], where the brackets denote molarity and the coefficients are the stoichiometric coefficients from the balanced equation.

Chemical Equilibrium

Chemical equilibrium occurs when the rates of the forward and reverse reactions are equal, resulting in constant concentrations of reactants and products over time. At this point, the system is in a state of balance, and the concentrations of all species involved remain unchanged, allowing for the calculation of Kc.

Stoichiometry in Equilibrium Expressions

Stoichiometry refers to the relationship between the quantities of reactants and products in a chemical reaction. In equilibrium expressions, the coefficients from the balanced chemical equation are used as exponents in the Kc expression, reflecting the proportionality of the concentrations of each species at equilibrium.