Reversible reactions and dynamic equilibrium

Answer Key - Grade 10 Science Worksheet - Building Confidence

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

1. 1.

   In N₂O₄ ⇌ 2 NO₂, 0.2 mol of N₂O₄ splits before equilibrium. How many moles of NO₂ form, Ari?

   0.4 mol
2. 2.

   In N₂O₄ ⇌ 2 NO₂, 0.15 mol of N₂O₄ splits before equilibrium. How many moles of NO₂ form, Bo?

   0.3 mol
3. 3.

   In N₂O₄ ⇌ 2 NO₂, 0.35 mol of N₂O₄ splits before equilibrium. How many moles of NO₂ form, Esme?

   0.7 mol
5. 4.

   Using the graph, when is equilibrium reached, Jun?

   • By about 30 s
   • At 0 s
   • At 10 s
6. 5.

   Using the graph, what is true of the two rates at equilibrium, Kira?

   Use the picture in question 4.

   • Both are zero
   • They are equal
   • Forward is double
7. 6.

   Using the graph, why does the forward rate fall at first, Luz?

   Use the picture in question 4.

   • Reactants are used up
   • The flask is cooling
   • Products block the arrow
8. 7.

   What does the arrow ⇌ in an equation mean, Milo?

   • It has stopped
   • It runs forward very fast
   • It runs both ways
9. 8.

   Do the reactions stop at equilibrium, Pia?

   • Yes: everything has stopped
   • No: both directions continue
   • Yes: one direction has ended
10. 9.

    At equilibrium, what are the amounts of reactants and products, Ren?

    • Constant, not always equal
    • Both falling to zero
    • Exactly equal to each other
11. 10.

    Why must a system be sealed to reach equilibrium, Tala?

    • So the rates can't change
    • So substances can't escape
    • So the light stays out