Can your students escape the Hillgrove Lab? In this high-energy stoichiometry performance task, they’ll balance equations, calculate yield, and reason backward through BCA tables to power up the reactor and open the doors!
In this immersive performance task, students become chemists trapped inside the Hillgrove Laboratory after a reactor malfunction. To escape, they must apply their knowledge of stoichiometry, BCA (Before-Change-After) tables, and conservation of matter to solve a sequence of “locks.” Each challenge integrates balancing equations, identifying limiting reactants, and calculating theoretical and percent yield.
The final lock requires students to work backward from a desired product to determine the exact quantities of reactants needed to reach 100% reactor efficiency—demonstrating full mastery of quantitative relationships in chemical reactions.
This task aligns with GSE Chemistry Standard SC3, emphasizing mathematical reasoning, modeling, and real-world applications. Designed for use in Formative SSO, it offers instant feedback and collaborative engagement while making complex chemistry concepts exciting and authentic.
Hillgrove Lab Lockdown: The Final Reaction ChallengeChemists, we’ve got a problem! The Hillgrove Lab reactor has stabilized, but the containment doors are still sealed. To escape, you must use your knowledge of stoichiometry, BCA tables, and limiting reactants to solve a series of chemistry “locks.” Each correct calculation powers the lab back online — and the final challenge requires you to work backward from the product to find exactly how much of each reactant is needed.
Can you balance the equations, restore full efficiency, and lift the doors before time runs out?
The chemical reactions in the balancing chamber are unstable.
__ N₂ + __ H₂ → __ NH₃
The chemical reactions in the balancing chamber are unstable.
__ Al + __ O₂ → __ Al₂O₃
The chemical reactions in the balancing chamber are unstable.
__ Fe₂O₃ + __ CO → __ Fe + __ CO₂
Balance each one to generate the override code (the sum of all coefficients in each reaction). Add the coefficients of each balanced equation above separately. Each sum corresponds to the code.
Enter your 3-digit code.
Example: If the sums of each reaction are:
3
9
4
then your code would be 3-9-4 → enter 394
Fill in the missing “Before” amount of H₂.
Reaction:
2H₂ + O₂ → 2H₂O
Step | H₂ (mol) | O₂ (mol) | H₂O (mol) |
|---|---|---|---|
Before | | 3.0 | 0 |
Change | –4x | –2x | +4x |
After | 0 | 1.0 | 4.0 |
Determine the missing “Change” value for N₂.
Reaction:
N₂ + 3H₂ → 2NH₃
Step | N₂ (mol) | H₂ (mol) | NH₃ (mol) |
|---|---|---|---|
Before | 2.0 | 6.0 | 0 |
Change | | –3x | +2x |
After | 1.0 | 0 | 4.0 |
Determine the missing “After” value for Al.
Reaction:
2Al + 3Cl₂ → 2AlCl₃
Step | Al (mol) | Cl₂ (mol) | AlCl₃ (mol) |
|---|---|---|---|
Before | 3.0 | 5.0 | 0 |
Change | –3.0x | –4.5x | +3.0x |
After | | 0.5 | 3.0 |
Use the first letter of the limiting reactant in each of the problems above to decode the numeric password. Use the Polybius key on the lab wall to decode the emergency phrase.
1 | 2 | 3 | 4 | 5 | |
|---|---|---|---|---|---|
1 | A | B | C | D | E |
2 | F | G | H | I/J | K |
3 | L | M | N | O | P |
4 | Q | R | S | T | U |
5 | V | W | X | Y | Z |
To encode, write the row and column numbers.
example: C O D E → 13-34-14-15
Start up the reactor:
System Alert: Reactor output below optimal range.
Maximum Calibrated Output: 25.4 g
Current Reactor Output: 21.6 g
The lab’s sodium chloride (NaCl) production is operating at partial efficiency.
What is the current efficiency yield?
To fully reboot the system, you must determine how much more product is required to reach 100% efficiency.
Proceed with caution — overcompensating may destabilize the reaction.
FINAL LOCK: Containment Door Override
Containment Door Override — Product Generation Required
Emergency Directive:
Reactor power stabilized at 100%, but the containment doors remain sealed.
To release the doors, the system requires exactly 1.81×1024 particles of the sodium chloride product.
Your task: Work backward to determine how much of each reactant must be supplied to generate the target product amount of
Input precise values (round to two decimals) (no units, just numbers), or the door will remain locked!
Step | ___Na | ___Cl₂ | ___NaCl |
|---|---|---|---|
Before | |||
Change | – | – | + |
After |
Reflect: In your own words, explain what this escape taught you about how limiting reactants and yield affect real chemical systems.
In this final calibration, you worked backward to find the exact reactant amounts needed to reach 100% efficiency. Explain how the ratio of reactants and products demonstrates the Law of Conservation of Matter.