Chemical Equilibrium

This following is true about the graph of the concentration of reactant and products againts time except:

• [A] decrease

• The system is in the state of equilibrium

• [B] decrease with time

• After certain time, [A] and [B] remains unchanged, but the reaction did not stop

At equilibrium, __________.

• all chemical reactions have ceased

• the rates of the forward and reverse reactions are equal

• the rate constants of the forward and reverse reactions are equal

• the value of the equilibrium constant is 1

• ) the limiting reagent has been consumed

2A + 3B <----> 2AB

The forward reaction forms the substance __________.

• A

• AB

• B

• A + B

Define chemical equilibrium.

• A reaction is reversible.

• A state where the concentration of the reactants is equal to the concentration of the products.

• A state where the rate of a forward reaction is equal to the rate of the reverse reaction.

• A state where the reaction stops and no further change in concentration occurs.

What is the K_c expression for this reaction?
   2 NO_(g)  +  O_2(g) ⇌  2 NO_2(g)

• K_c = [NO₂]² / [NO]² [O₂]
• K_c =  [NO]² [O₂] / [NO₂]²
• K_c = [NO]² [O₂] [NO₂]²
• K_c = [NO₂]² / [NO]² +  [O₂]

Tags

NGSS.HS-PS1-7

What are [A] and [B]?

• concentration of reactants
• concentration of products
• energy of reactants
• energy of products

Tags

NGSS.HS-PS1-5

NGSS.HS-PS1-6

What is the equilibrium expression for:
Fe₃O₄(s) + 4H₂(g) <=> 3Fe(s) + 4H₂O(g)
K_c =

• [Fe]³ [H₂O]⁴  / [Fe₃O₄] [H₂]⁴
• [Fe₃O₄] [H₂]⁴ /  [Fe]³ [H₂O]⁴
• [H₂O]⁴ / [H₂]⁴
• [Fe] [H₂O] / [Fe₃O₄] [H₂]

Tags

NGSS.HS-PS1-6

The Kc expression for the reaction 2NH₃ ⇌ N₂ + 3H₂

• 
• 
• 
• 

Tags

NGSS.HS-PS1-7

If the reaction quotient Q has a smaller value than the related equilibrium constant, K, _________

• the reaction is at equilibrium

• the reaction is not at equilibrium, and will make more products at the expense of the reactants

• the reaction is not at equilibrium, and will make more reactants at the expense of the products

• the value of K will not increase until it is equal to Q

Tags

NGSS.HS-PS1-7

At elevated temperatures ammonium carbonate, NH₂COONH₄, is in equilibrium with NH₃ and CO₂ according to the equation;

NH₂COONH₄(s) ↔ 2 NH₃(g) + CO₂(g)

What is the equilibrium expression for this reaction?

• K = 2 [NH₃][CO₂]

  [NH₂COONH₄]

• K = [NH₃]²[CO₂]

  [NH₂COONH₄]

• K = 2 [NH₃][CO₂]

• K = [NH₃]²[CO₂]

Tags

NGSS.HS-PS1-6