AP Chem Unit 07 Days 03-04 Practice

A mixture consisting of 0.250 mol N₂(g) and 0.500 mol H₂(g) in a 1.0 liter flask reaches equilibrium according to the equation

N₂(g) + 3 H₂(g) ⇄ 2 NH₃(g)

At equilibrium, there are 0.150 mol of ammonia. Calculate the number of moles of H₂(g) at equilibrium.

• 0.175 mol H₂

• 0.275 mol H₂

• 0.425 mol H₂

• 0.075 mol H₂

A(g) + 2B(g) ⇄ C(g) + 2D(g)

Equal numbers of moles of A and B are placed in a rigid flask at a given temperature and allowed to reach equilibrium according to the equation above. Which of the following must be true at equilibrium?

• The [A] must be less than the [B], and [C] must equal [D].

• The [A] must be less than the [B], and [C] will differ from [D].

• The [A] must be greater than the [B], and [C] must equal [D].

• The [A] must be greater than the [B], and [C] will differ from [D].

CO₂(g) + H₂(g) ⇄ H₂O(g) + CO(g)

H₂O(g) and CO(g) are inserted into an evacuated, rigid flask so that the initial partial pressures of each of them are 2.40atm and 1.80atm respectively. The reaction is carried out at constant temperature. What is the partial pressure of H₂(g) when the partial pressure of H₂O(g) has decreased to 1.60atm?

• 0.80atm

• 1.00atm

• 1.20atm

• 1.60atm

Consider the reaction

PCl₅(g) ⇄ PCl₃(g) + Cl₂(g)

At a certain temperature, the initial concentration of PCl₅(g) is 8.0 M and at equilibrium the concentration of Cl₂(g) is 6.0 M. Calculate the value of K_c at this temperature.

• 2.0

• 6.0

• 18

• 36

Tags

NGSS.HS-PS1-7

A(g) + 2B(g) ⇄ C(g) + 2D(g)

When 1.5 mole of A and 2.0 mole of B are placed in an evacuated 1.00-liter flask, the reaction represented above occurs. After the reactants and the product reach equilibrium and the initial temperature is restored, the flask is found to contain 0.75 mole of C. Based on these results, the expression for the equilibrium constant, K_c, of the reaction is

• 
• 
• 
• 

Tags

NGSS.HS-PS1-7

H₂(g) + I₂(g) ⇄ 2 HI(g)

 

The equilibrium constant, K_c, for the reaction above is 25 at 298K. If 28.0 mol of HI are introduced into a 2.00 liter vessel, how many moles of HI are present at equilibrium?

• 2.0 moles HI

• 4.0 moles HI

• 10.0 moles HI

• 20.0 moles HI

Tags

NGSS.HS-PS1-7

NGSS.HS-PS1-6