The equilibrium constant, K

Answer Key - Grade 10 Science Worksheet - Building Confidence

Circle the best answer, or write your answer on the line.

1. 1.

   At equilibrium for A ⇌ B, [A] = 0.2 mol/L and [B] = 0.6 mol/L. What is K, Ari?

   3
2. 2.

   At equilibrium for A ⇌ B, [A] = 0.5 mol/L and [B] = 0.1 mol/L. What is K, Bo?

   0.2

3. Read this first

   Concentration against time for A ⇌ B, leveling off (example data)

   time (s)	[A] (mol/L)	[B] (mol/L)
   0	1	0
   10	0.6	0.4
   20	0.4	0.6
   30	0.25	0.75
   40	0.25	0.75

4. 3.

   Using the graph, by when has the reaction reached equilibrium, Jun?

   • By 30 s
   • At 0 s
   • At 10 s
5. 4.

   Using the graph's equilibrium values, what is K for A ⇌ B, Kira?

   • 0.33
   • 3
   • 0.75
6. 5.

   Using the graph, is the equilibrium mixture mostly A or mostly B, Luz?

   • Exactly half and half
   • Mostly B, the product
   • Mostly A, the reactant
7. 6.

   How is K set up, Milo?

   • Reactants over products
   • Products times reactants
   • Products over reactants
8. 7.

   What is K for A ⇌ 2 B, Noah?

   • [A] ÷ [B]²
   • 2[B] ÷ [A]
   • [B]² ÷ [A]
9. 8.

   In a K expression, what do the equation's coefficients become, Pia?

   • Nothing: they're left out
   • Numbers added to the top
   • Powers on each concentration
10. 9.

    A reaction has K = 1 × 10¹⁰. What does its equilibrium mixture mostly hold, Ren?

    • Products
    • Equal amounts
    • Reactants
11. 10.

    A reaction has K = 1 × 10⁻⁵. What does its equilibrium mixture mostly hold, Tala?

    • Equal amounts
    • Products
    • Reactants