Reversible and Irreversible Reactions and Chemical Equilibrium

What type of reactions can able to change products back to the their original form?

• Reversible reactions

• Irreversible reactions

• Combustion reactions

• Combination reactions

If a reversible reaction is exothermic in the forward direction, it will be ...

• exothermic in the reverse direction

• endothermic in the forward direction too

• endothermic in the reverse direction

• not involve energy in reverse direction

Tags

NGSS.HS-PS1-4

What is the symbol which is used in reversible reactions?

• →

• Δ

• +

• ⇌

What is a closed system

• It gives out energy

• The reactants and the products do not escape from reaction mixture

• It takes in energy

• The reactants and the products escape from he reaction mixture to be kept in the system

Tags

NGSS.HS-PS3-4

Define chemical equilibrium.

• A reaction is reversible.
• The concentration of the reactants is equal to the concentration of the products.
• The rate of a forward reaction is equal to the rate of the reverse reaction.
• The reaction stops and no further change in concentration occurs.

Tags

NGSS.HS-PS1-6

The picture shows a reversible chemical reaction taking place. How can equilibrium be reached?

• Stopper the flask.
• Add more reactants.
• Add more products.
• Cool the contents.

Tags

NGSS.HS-PS1-5

NGSS.HS-PS1-6

How does a catalyst change during a reaction?

• It is part of the products
• It combines with the reactants
• It precipitates
• It remains unchanged

For the reaction...
N₂  +  O₂  <=>  2NO
If  O₂ is removed, the  concentration of N₂ will _______.

• increase
• decrease
• remain the same
• double

Tags

NGSS.HS-PS1-5

For the reaction...
N_{2 (g)} +  3 H_2 (g) <=> 2 NH_{3 (g)}

If the pressure in the system is increased,  which substance(s) will increase in concentration?

• N₂  (as 2 mol gas  → 4 mol gas)
• H₂ (as 2 mol gas  → 4 mol gas)
• N₂ and H₂ (as 2 mol gas  → 4 mol gas)
• NH₃ (as 4 mol gas  → 2 mol gas)

Le Chatelier's Principle states that.... 
If a (dynamic) equilibrium is disturbed by changing the conditions, the position of equilibrium................

• moves to increase the change
• moves to counteract the change
• does not change