Equilibrium: Quantative Problems

2.50 mol NOCl was placed in a 2.50 L reaction vessel at 400ºC.  After equilibrium was established, it was found that 28% of the NOCl had dissociated according to the equation 2NOCl(g) <-> 2NO(g) + Cl2(g). Calculate the equilibrium constant, Kc, for the reaction.

• 0.021
• 0.039
• 0.169
• 26

For the reaction SO₂(g) + NO₂(g) <-> SO₃(g) + NO(g), the equilibrium constant is 18.0 at 1,200ºC.  If 1.0 mole of SO₂ and 2.0 moles of NO₂ are placed in a 20. L container, what concentration of SO₃ will be present at equilibrium?

• 0.11 M
• 0.95 M
• 0.48 M
• 2.22 M

Given: 2A(g) <-> 2B(g) + C(g). At a particular temperature, K = 1.6x10⁴.
At a higher temperature, K = 1.8x10^-5. Placing the equilibrium mixture in an ice bath (thus lowering the temperature) will...

• cause [A] to increase
• cause [B] to increase
• gave no effect
• cannot be determined

Tags

NGSS.HS-PS1-5

NGSS.HS-PS1-6

Given: 2A(g) <-> 2B(g) + C(g). At a particular temperature, K = 1.6x10⁴.
Raising the pressure by lowering the volume of the container will...

• cause [A] to increase
• cause [B] to increase
• have no effect
• cannot be determined

What is the proper K_eq for the following 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 = 2[NO][O₂] / 2[NO₂]

Tags

NGSS.HS-PS1-7

An equilibrium constant with a large magnitude indicates…

• A very fast reaction
• More products at equilibrium
• More reactants at equilibrium
• nothing, without considering the stoichiometry of the reaction

Initially, 0.84 moles of PCl₅(g) is placed in a 1.0L flask.  At equilibrium, 0.72 moles of PCl₅(g) is present.  What is the value of Kc for this reaction?
PCl₅(g) ↔ PCl₃(g) + Cl₂(g)

• 0.62
• 0.020
• 0.72
• 0.12

A 2.21L vessel was found to contain 0.0418 mol of CO2, 0.0281 mol of CO and 0.00889 mol of O2.  Is the system at equilibrium for the following reaction?  If not, which direction must the reaction proceed to achieve equilibrium?
2CO₂(g) ↔ 2CO(g) + O₂(g)  Kc = 1.2 x 10^-13

• Yes
• No, to the right
• No, to the left
• Not enough info given

Determine the value of the equilibrium constant for this reaction if an initial concentration of N₂O₄(g) of 0.0400 mol/L is reduced to 0.0055 mol/L at equilibrium.  There is no NO₂(g) present at the start of the reaction.
N₂O₄(g) ↔ 2NO₂(g)

• 13
• 0.87
• 0.22
• 0.022

Tags

NGSS.HS-PS1-7

A mixture of 0.500 mol H₂ and 0.500 mol I₂ was placed in a 1.00L flask.  The equilibrium constant Kc for the reaction H₂(g) + I₂(g) ↔ 2HI(g) is 54.3.  What is the concentration of HI at equilibrium?

• 0.5M
• 1.0M
• 0.786M
• 0.393M