Question

question 5 the equilibrium equation can be solved without using the quadratic formula if... the equation is a perfect square. the change in the concentration is more than 10% of the initial concentration of the reactant. the kc is less than 1. the equilibrium concentration of the reactants is 50% of their initial concentration. question 6 using the ice table method, how is the value of x related to the change in concentration of products and reactants? directly proportional to the stoichiometric coefficients. inversely proportional to the equilibrium constant. equal to the difference between initial and equilibrium concentrations. not related to the stoichiometric coefficients.

Explanation:

Step1: Recall ICE - table concept

In an ICE (Initial - Change - Equilibrium) table, the change in concentration of products and reactants ($x$) is directly proportional to the stoichiometric coefficients of the species in the balanced chemical equation. For example, if the reaction is $aA + bB
ightleftharpoons cC + dD$, the change in concentration of $A$ is $-ax$, of $B$ is $-bx$, of $C$ is $+cx$ and of $D$ is $+dx$.

Step2: Recall approximation for equilibrium calculations

When $K_c$ is less than 1 and the change in concentration is less than 10% of the initial concentration of the reactant (i.e., the equilibrium concentration of the reactants is 50% or more of their initial concentration), we can make simplifying approximations to avoid using the quadratic formula. This is because the reaction does not proceed to a large extent and the change in concentration ($x$) is small compared to the initial concentration.

Answer:

Question 5: The equilibrium equation can be solved without using the quadratic formula if the $K_c$ is less than 1 and the change in the concentration is less than 10% of the initial concentration of the reactant and the equilibrium concentration of the reactants is 50% of their initial concentration.
Question 6: Using the ICE - table method, the value of $x$ (change in concentration of products and reactants) is directly proportional to the stoichiometric coefficients.