Unit 7 Study Guide

Which of the following are true at Equilibrium:

I. The reaction stops completely

II. The reaction of the forward and reverse reactions are at the same rate

III. The concentrations of products and reactants are the same

IV. The concentrations of products and reactants stop changing

• I, II, and III

• II, and III

• II and IV

• I and III

• IV only

Tags

NGSS.HS-PS1-6

At what time is equilibrium reached according to the data above?

• 60s

• 90s

• 120s

• 180s

Tags

NGSS.HS-PS1-5

At what time does the above reaction reach equilibrium according to the graph?

• 75s

• 100 s

• 125s

• 150 s

4. Equilibrium Equations
a. The general formula for the equilibrium expression is:

• K = [products]/[reactants]

• K = [reactants]/[products]

• K = [products] + [reactants]

• K = [reactants] - [products]

What are the ONLY phases (states of matter) we include in equilibrium expressions?

• Solids and liquids

• Gases and aqueous solutions

• Gases only

• Gases and liquids

Write the equilibrium expression for: 2A(g) + 3B(g) ⇌ 4C(g) + D(g)

Write the equilibrium expression for the following system: a. C3H8(g) + 5O2(g) ⇌ 3CO2(g) + 4H2O(g)

Write the equilibrium expression for the following system:
b. N2O4(g) + O3(g) ⇌ N2O5(s) + O2(g)

• K = [O2]/([N2O4][O3])

• K = [N2O4][O3]/([N2O5][O2])

• K = [N2O5][O3]/([N2O4][O2])

• K = [N2O4][O2]/([N2O5][O3])

Write the equilibrium expression for the following system: c. 2NO2(g) ⇌ N2(g) + O2(g)

• Kc = [N2]/[NO2][O2]

• Kc = [NO2]/[N2][O2]

6. Solve for K for the following system:
a. PCl5(g) ⇌ PCl3(g) + Cl2(g)
[PCl5(g)] = 0.200M
[PCl3(g)] = 0.040M
[Cl2(g)] = 0.080M
What is the value of the equilibrium constant (K) for the reaction?

• 0.016

• 0.020

• 0.080

• 0.040

Tags

NGSS.HS-PS1-7