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
4. 3.

   Using the graph, when is equilibrium reached, Jun?

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

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

   Use the picture in question 3.

   • They are equal
   • Both are zero
   • Forward is double
6. 5.

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

   • It has stopped
   • It runs both ways
   • It runs forward very fast
7. 6.

   Which of these changes can go both ways, Noah?

   • A log burning to ash
   • An egg being fried
   • Water freezing and melting
8. 7.

   Do the reactions stop at equilibrium, Pia?

   • No: both directions continue
   • Yes: one direction has ended
   • Yes: everything has stopped
9. 8.

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

   • Exactly equal to each other
   • Both falling to zero
   • Constant, not always equal
10. 9.

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

    • So substances can't escape
    • So the light stays out
    • So the rates can't change
11. 10.

    In a sealed tube of bromine, liquid and vapor reach equilibrium. What does that mean, Zee?

    • The liquid has turned fully to vapor
    • The vapor has condensed back fully
    • Evaporating and condensing match