Topic 7.1

Which statement is not correct for a reaction at equilibrium?

• The forward and reverse reactions both continue.
• The rates of the forward and reverse reactions are equal.
• The concentration of the products and reactants are equal.
• All of these statements are correct.

Which statement is always true for a chemical reaction that has reached equilibrium at a constant temperature?

• The yield of product(s) is greater than 50%.
• The rate of the reverse reaction is lower than that of the forward reaction.
• The amounts of reactants and products do not change.
• Both forward and reverse reactions have stopped. 

Tags

NGSS.HS-PS1-6

Which statement is NOT true for a mixture of ice and water at equilibrium at a constant temperature?

• The rates of melting and freezing are equal.
• The amounts of ice and water are equal.
• The same position of equilibrium can be reach by cooling water and heating ice.
• There is no observable change in the system. 

Tags

NGSS.HS-PS3-2

When the following equation, N₂ + 2H₂ <--> N₂H₄, reaches equilibrium, it has a K_c value of 7.4 x 10^-26.  Does the mixture of these molecules contain mostly products or reactants? 

• Products, because K_c << 1
• Reactants, because K_c << 1
• Products, because K_c >> 1
• Reactants, because K_c >> 1

When the following equation, N₂ + O₂ <--> 2NO, reaches equilibrium, it has a K_c value of 2.7 x 10^-18.  Does the mixture of these molecules contain mostly products or reactants? 

• Products, because K_c << 1
• Reactants, because K_c << 1
• Products, because K_c >>1
• Reactants, because K_c >>1

When the following equation, N₂ + 2H₂ <--> N₂H₄, reaches equilibrium, it has a K_c value of 7.4 x 10^-26.  Does the mixture of these molecules contain mostly products or reactants? 

• Products, because K_c << 1
• Reactants, because K_c << 1
• Products, because K_c >> 1
• Reactants, because K_c >> 1