Statue Savior Slides Reaction Rescue
Case File: The Corroded Statue
Urgent Memo
The city's historic "Guardian of the Bay" bronze statue is turning bright green and showing signs of rapid structural failure.
Current Estimate: Complete collapse in 72 hours.
Your Mission:
Determine if this is natural weathering or a chemical sabotage. Propose a solution before the monument is lost forever.
Evidence #042
Forensic Toolkit: Chemical Changes
Color Change
Unexpected shifts in hue (like bronze turning green) indicate new substances forming.
Energy Shift
Release of heat (exothermic) or absorption (endothermic) during the process.
Gas Release
Bubbling or fizzing (effervescence) shows a gas product is escaping the system.
Which of these signs are we seeing on the Guardian of the Bay?
Law of the Lab
"Mass is neither created nor destroyed."
Reactants
Input
Products
Output
If the statue is losing mass, where is that matter going?
Operational Phases
01
Analyze Samples
Identify the reactants causing the corrosion.
02
Reaction Modeling
Determine the type of reaction taking place.
03
Neutralization Plan
Stop the reaction without causing further damage.
Refer to your Investigation Dossier to begin...
Investigation Dossier Worksheet Confidential
Investigation Dossier
Case #CH-STATUE-042 // Bureau of Scientific Inquiry
AGENT: ________________
DATE: _________________
Incident Summary
The copper-plated "Guardian of the Bay" statue was accidentally sprayed with an "extreme strength" industrial cleaner (Hydrochloric Acid). Within hours, the surface began to bubble and turn a sickly bluish-green. Lab technicians collected samples of the reactant and products for analysis.
Phase 1: Evidence Analysis
Lab Observation Log
Bubbles of colorless gas formed immediately on the surface.
Exothermic reaction: Surface temperature rose by 15°C.
Formation of bluish-green copper(II) chloride crust.
Scientific Claim
List three signs of a chemical reaction found in the log:
Phase 2: Reaction Modeling
Chemical Equation Breakdown
Cu + 2HCl → CuCl2 + H2
1. Classify this reaction type:
Synthesis
Decomposition
Single Replacement
Double Replacement
2. Atom Count (Conservation of Mass):
Reactants
Cu: _______ H: _______ Cl: _______
Products
Cu: _______ H: _______ Cl: _______
Where did the "missing" mass go?
Phase 3: Neutralization Strategy
Baking Soda
(pH 9.0 Base)
Water
(pH 7.0 Neutral)
Vinegar
(pH 3.0 Acid)
Recommendation Report: Explain your choice and the science behind it.
Lab Supervisor Guide Chief Chemist Guide
TEACHER RESOURCE
Lesson: Statue Savior (PBL Investigation)
Instructional Focus
This problem-based learning (PBL) activity challenges students to apply their knowledge of chemical reactions to a "real-world" forensic scenario. Students must identify signs of chemical change, classify reaction types, and apply the Law of Conservation of Mass.
Key Concepts
Single Replacement
Exothermic Reaction
Conservation of Mass
Acid/Base Neutralization
Implementation Roadmap
10
Phase 1: The Hook
Present the scenario with the slides. Use the "72-hour" deadline to build urgency. Ask: "What causes copper to change color so quickly?"
25
Phase 2: Data Analysis
Students complete the Investigation Dossier . Note: Ensure they identify that the "missing mass" is actually the gas escaping into the atmosphere.
15
Phase 3: Debrief
Teams share strategies. Explain that adding more acid (vinegar) would accelerate the damage, while water only dilutes it.
Forensic Solution Key
Signs of Change
Bubbling (Gas), Temperature rise (Exothermic), Color shift (Shiny Brown to Bluish-Green).
Reaction Type
Single Replacement: Cu + 2HCl → CuCl2 + H2
Conservation of Mass
Mass is conserved. The H2 gas escaped into the atmosphere, causing the apparent mass loss.
Neutralization
Baking Soda:
A base that reacts with HCl to neutralize it, forming saltwater and CO2.
Common Misconceptions
• "Mass was destroyed": Students often think mass disappears when gas is released. Remind them atoms are just rearranged into invisible gaseous molecules.
• "Color change = Physical": Clarify that a permanent, unexpected color change (not just mixing paint) is chemical.
Safety Protocols
• If performing a lab demo, always wear goggles and gloves when handling HCl or strong bases.
• Ensure the classroom is well-ventilated during gas-releasing reactions.
• Neutralize all acid spills with baking soda before cleaning.
