Question

question 21 (10 points)
match each item to the correct statement below.
this reaction proceeds at a
faster rate when thermal
energy is removed from a
system
another name for law of
mass action
expression indicating that
reactant formation is
favoured

1. equilibrium

a system in which matter
and energy do not cross
the system’s boundary

1. closed system

a rule that states that if a
chemical system at

1. law of chemical equilibrium

equilibrium is distributed
the system will undergo a
shift

1. $k_{eq} > 1$

expression indicating that
product formation is
favoured

1. $k_{eq} < 1$

expression indicating
approximately the same
reactant and product
formation

1. $k_{eq} = 1$

the general form of an
equilibrium reaction

1. $aa + bb \hat{u} cc + dd$

this reaction proceeds at a
faster rate when thermal
energy is added to a
system

1. exothermic reaction
2. endothermic reaction

a state in which opposing
forces or processes are
balanced

1. le chatelier’s principle

Explanation:

• For "this reaction proceeds at a faster rate when thermal energy is removed from a system": Exothermic reactions release heat. Removing thermal energy (lowering temperature) will shift the equilibrium of an exothermic reaction to the right (faster forward rate) according to Le Chatelier's principle. So it matches with "exothermic reaction".
• For "another name for law of mass action": The law of chemical equilibrium is another name for the law of mass action.
• For "expression indicating that reactant formation is favoured": When \(K_{eq}< 1\), the concentration of reactants is higher than that of products at equilibrium, so reactant formation is favoured.
• For "a system in which matter and energy do not cross the system’s boundary": This is not a standard concept in chemical equilibrium. But if we consider the options, there is no perfect match. However, if we assume it's a wrong - phrased question (maybe it was supposed to be a system where only energy can cross), but among the given options, there is no correct one. But if we consider the closest wrong - option, there is no proper one. But if we assume it's a misprint and was supposed to be a closed system (where matter does not cross), but energy can. But the description is wrong. However, among the options, we might skip this as there is a mistake in the question's description.
• For "a rule that states that if a chemical system at equilibrium is disturbed the system will undergo a shift": This is Le Chatelier's principle.
• For "expression indicating that product formation is favoured": When \(K_{eq}>1\), the concentration of products is higher than that of reactants at equilibrium, so product formation is favoured.
• For "expression indicating approximately the same reactant and product formation": When \(K_{eq} = 1\), the concentrations of reactants and products are approximately the same at equilibrium.
• For "the general form of an equilibrium reaction": \(aA + bB

ightleftharpoons cC + dD\) is the general form of an equilibrium reaction.

• For "this reaction proceeds at a faster rate when thermal energy is added to a system": Endothermic reactions absorb heat. Adding thermal energy (raising temperature) will shift the equilibrium of an endothermic reaction to the right (faster forward rate) according to Le Chatelier's principle. So it matches with "endothermic reaction".
• For "a state in which opposing forces or processes are balanced": This is the definition of equilibrium.

Answer:

• "this reaction proceeds at a faster rate when thermal energy is removed from a system": 8. exothermic reaction
• "another name for law of mass action": 3. law of chemical equilibrium
• "expression indicating that reactant formation is favoured": 5. \(K_{eq}<1\)
• "a rule that states that if a chemical system at equilibrium is disturbed the system will undergo a shift": 10. Le Chatelier's principle
• "expression indicating that product formation is favoured": 4. \(K_{eq}>1\)
• "expression indicating approximately the same reactant and product formation": 6. \(K_{eq}=1\)
• "the general form of an equilibrium reaction": 7. \(aA + bB

ightleftharpoons cC + dD\)

• "this reaction proceeds at a faster rate when thermal energy is added to a system": 9. endothermic reaction
• "a state in which opposing forces or processes are balanced": 1. equilibrium