Ruating investigation

Part A — Predicting & Identifying the Reaction

1. Predicting Products

A bench is made of iron (Fe) or steel (an alloy that is a mix of iron and carbon) and is left outside where it is exposed to oxygen (O₂) and water (H₂O).
a. Write a word equation predicting what substances will form when iron reacts with oxygen and water.
b. Convert your word equation into a chemical equation. (Hint: one of the products is “Hydrated iron(III) oxide”... what is left over?)

 c. Challenge: Balance the chemical equation you’ve just written. (check with your teacher first to make sure the formulas are correct!)


2. Reaction Type

a. Identify what type of chemical reaction rusting is (e.g., synthesis, decomposition, single replacement, double displacement, etc.).
b. Explain why rusting fits this reaction type, using evidence from your equation.

Part B — Modeling the Reaction

3. Particle-Level Diagram

Draw a simple diagram (with labels!) that shows at the atomic level:

  • The reactants of the reaction

  • The arrangement of particles after rust [hydrated iron (III) oxide] has formed.

4. System Diagram

Draw an input–process–output diagram showing:

  • Inputs: materials required for rusting

  • Process: what happens to cause rusting

  • Outputs: substances formed and observable effects

Part C — Data Analysis

You conducted an experiment where four identical iron nails were placed in different conditions for one week.

Condition

Setup

Mass of nail before (g)

Mass of nail after (g)

Visible Rust (0–5 scale)

A

Exposed to air only

3.50

3.52

1

B

Completely submerged in water

3.50

3.54

2

C

Saltwater

3.50

3.60

5

D

Nail coated in oil

3.50

3.50

0

5. Making Observations

   a. Which condition produced the most rust?
  b. What evidence from the data supports your conclusion?
  c. Which variable changed between the conditions?                                                                       d. Did we break the law of conservation of mass in this experiment? Explain why / why not…        


6. Interpreting the Data

a. Explain why saltwater increases rusting the most… (hint: what is the extra component, and why might it increase this reaction? Think golden gate bridge)
b. Why does the oil-coated nail not rust?

Part D — Applying Understanding

7. Recognizing the difference

  1. Knowing what you know now, how can you explain the difference between the benches that have starting getting rusty versus the ones that have stayed shiny?

8. Evaluating the Experiment

 a. Identify one source of error or limitation in the nail experiment.
b. Suggest an improvement and explain how it would increase reliability or validity.

Part E - The law of conservation of mass/matter

  1. If iron oxide (rust) has a greater mass than the original iron, what does this reveal about the reaction? Explain in terms of conservation of mass and the substances being added to iron during rusting.

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EXTENSION



CLAIM: Rusting a chemical reaction that requires certain reactants in order to happen.


EVIDENCE: (3-5 pieces)


REASONING: (5-7 sentences)