Chemical equilibrium

Label the parts of the reaction diagram.

a

b

c

activation energy

products

reactants

Which of the following would increase the rate of reaction? Select ALL correct answers.

• Addition of a catalytst

• Increasing the temperature

• Decreasing activation energy

• Decreasing the energy of the products

• Increasing the concentration of reactants

Tags

NGSS.HS-PS1-5

Reaction rates are increased by ​ (a)   the ​ (b)   between reactants.

• increasing
• frequency of collisions
• decreasing
• energy difference

Tags

NGSS.HS-PS1-5

In exothermic reactions, energy is ​ (a)   .

In endothermic reactions, energy is ​ (b)   .

• released
• absorbed

Answer explanation

Remember the "exo" sounds like "exit"

In exothermic reactions, energy exits (energy is released)

Remember the "endo" sounds like "into"

In endothermic reactions, energy go into (energy is absorbed)

Tags

NGSS.HS-PS1-4

What does it mean for a chemical reaction to be in equilibrium?

• No net change in the concentrations of reactants and products
• The reaction has only products and no reactants
• The reaction is proceeding very slowly
• The reaction has stopped completely

Tags

NGSS.HS-PS1-6

What is the equilibrium-constant expression for 
CO₂(g) + H₂(g) ↔ CO(g) + H₂O(l)

• K_c= [CO][H₂O] / [CO₂][H₂]  
• K_c= [CO₂][H₂] / [CO]
• K_c= [CO₂][H₂] / [CO][H₂O]
• K_c= [CO] / [CO₂][H₂]  

This symbol indicates that a reaction is ____________

• reversible
• irreversible

Tags

NGSS.HS-PS1-6

When the rate of the forward reaction is equal to the rate of backward reaction, the system is said to be in

• Chemical Equilibrium
• Chemical Balance
• Stoichiometry
• Chemical Reaction

Tags

NGSS.HS-PS1-6

Which of the following is NOT true at equilibrium?

• The forward and reverse reactions proceed at the same rate.
• The concentrations of reactants and products do not change.
• The concentration of the reactants is equal to the concentration of the products.
• The forward and reverse reactions continue to occur.

What is the K_eq expression for this reaction?

2 NO_(g) + O_2(g) ⇌ 2 NO_2(g)

• K_eq = [NO₂]² / [NO]² [O₂]

• K_eq = [NO]² [O₂] / [NO₂]²

• K_eq = [NO]² [O₂] [NO₂]²

• K_eq = [NO₂]² / [NO]² + [O₂]