Reversible reactions and dynamic equilibrium

Answer Key - Grade 10 Science Worksheet - Challenge Me

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

1. 1.

   In N₂ + 3 H₂ ⇌ 2 NH₃, a sealed vessel starts with 3 mol of H₂, and 0.4 mol of N₂ reacts before equilibrium. How many moles of H₂ remain, Ari?

   1.8 mol
2. 2.

   In N₂ + 3 H₂ ⇌ 2 NH₃, a sealed vessel starts with 6 mol of H₂, and 1.2 mol of N₂ reacts before equilibrium. How many moles of H₂ remain, Bo?

   2.4 mol
3. 3.

   In N₂ + 3 H₂ ⇌ 2 NH₃, a sealed vessel starts with 1.5 mol of H₂, and 0.2 mol of N₂ reacts before equilibrium. How many moles of H₂ remain, Esme?

   0.9 mol
4. 4.

   A sealed jar holds some water. Once it reaches equilibrium, what stays constant, Jun?

   • Nothing: it keeps drying out
   • The jar keeps filling with vapor
   • The amount of water vapor
5. 5.

   Why doesn't water in an open pot on a stove reach equilibrium with its vapor, Luz?

   • The pot is too small
   • Vapor escapes
   • Water can't evaporate
6. 6.

   Milo says reactants and products have equal amounts at equilibrium. Agree or disagree?

   • Disagree: amounts are steady, not equal
   • Agree: the reactions stop halfway
   • Agree: balance means the amounts match
7. 7.

   Noah says the table never reached equilibrium because 0.050 isn't equal to 0.100. Agree or disagree?

   • Agree: the flask was open
   • Agree: equilibrium needs matching amounts
   • Disagree: the amounts stopped changing
8. 8.

   Pia says both reactions stop once equilibrium is reached. Agree or disagree?

   • Agree: the particles stop moving
   • Disagree: they run at equal rates
   • Agree: the rates both fall to zero
9. 9.

   How can data show that a system has reached equilibrium, Tala?

   • The amounts become equal
   • The amounts stop changing
   • One amount reaches zero
10. 10.

    Can a system at equilibrium hold mostly products, Zee?

    • No: it must be mostly reactant
    • No: it must be half and half
    • Yes: amounts can be very different