Report For Experiment 12 Single Displacement Reactions

You stare at the test tube. And you wait. Still nothing. Because of that, nothing happens. Plus, your lab partner checks the procedure for the third time. The copper wire sits in the silver nitrate solution like it's on vacation, and you're starting to wonder if you grabbed the wrong metal strip — or if the solution was made up wrong, or if you're just missing something obvious.

That moment? That's Experiment 12 in a nutshell.

Single displacement reactions look clean on paper. Done. But in the lab, they're messy, subtle, and occasionally stubborn. Metal A kicks Metal B out of its compound. This guide walks through what the experiment actually tests, where students trip up, and how to write a report that doesn't read like a copy-paste from the manual.

What Is Experiment 12

Most general chemistry lab sequences slot single displacement reactions around the twelfth week — hence the number. Because of that, the core idea is straightforward: you test a handful of metals against a handful of cation solutions to see which combinations react. The results let you build or confirm an activity series.

The typical lineup

You'll usually work with four to six metals — think copper, zinc, magnesium, iron, lead, maybe tin — and a matching set of nitrate or sulfate solutions. Because of that, copper(II) nitrate, zinc nitrate, magnesium sulfate, iron(III) nitrate, lead(II) nitrate. So naturally, the metals go into the solutions. You watch for color changes, precipitate formation, gas bubbles, temperature shifts.

Some versions add hydrochloric acid or water to test hydrogen displacement. Others include a halogen displacement section (chlorine water with bromide/iodide solutions). The principle stays the same: a more reactive element displaces a less reactive one from its compound.

What you're actually measuring

Not "does it react." That's binary and boring. You're measuring relative* reactivity. The pattern across all combinations — which metals displace which ions — is the data. And a single "no reaction" result tells you as much as a vigorous one. Maybe more.

Why It Matters

This experiment shows up in every introductory chemistry course for a reason. It's not just about memorizing that zinc beats copper. It's the first time many students see redox chemistry as something tangible — electrons moving from one species to another, visible consequences in a test tube.

The activity series isn't arbitrary

Textbooks hand you a list: K > Na > Ca > Mg > Al > Zn > Fe > Ni > Sn > Pb > H > Cu > Ag > Au. So experiment 12 is where that list earns its keep. So you're not memorizing it. Plus, you're deriving* it. Or at least verifying a slice of it.

Redox becomes real

Oxidation numbers on a whiteboard are abstract. The silver reduces. Electrons flow. The copper oxidizes. Watching copper metal turn a blue solution colorless while the wire grows silver fuzz? That's Cu(s) + 2Ag⁺(aq) → Cu²⁺(aq) + 2Ag(s) happening right in front of you. You can see the evidence.

It sets up electrochemistry

Galvanic cells, standard reduction potentials, the Nernst equation — they all trace back to the same reactivity hierarchy you're mapping in this lab. If you understand why magnesium displaces iron but not aluminum, half-cells make sense later. If you don't, they're just formulas to memorize.

How It Works (and How to Run It Clean)

The procedure varies by manual, but the logic is consistent. Here's the version that shows up most often, with the details that actually matter.

Step 1: Clean your metals

This sounds trivial. It's not. Oxidation layers, skin oils, and residual chemicals from storage all kill reactivity. Sand each metal strip until it's shiny. Here's the thing — rinse with deionized water. In real terms, don't touch the cleaned surface with your fingers. Hold it with forceps or the very edge.

I've seen entire lab sections get "no reaction" across the board because someone skipped the sanding step. Worth adding: the oxide layer on aluminum is especially stubborn — it reforms in seconds. Sand, rinse, test immediately.

Step 2: Organize the well plate

Use a 24-well plate or a rack of small test tubes. Label rows by metal, columns by solution. Even so, or vice versa. Just be consistent. Because of that, put ~1 mL of each solution in its wells first. Then add metals. Doing it the other way around (metal first, then solution) makes it harder to see the initial reaction moment.

Step 3: Observe at intervals

Don't just glance and move on. Some reactions are instant (magnesium in acid). Some take time (lead in copper(II) nitrate). Record at 30 seconds, 2 minutes, 10 minutes, 30 minutes. Some look like "no reaction" until you come back after lunch and see a delicate crystal forest growing on the wire.

What to note:

• Color change in solution
• Color/texture change on metal surface
• Gas bubbles (where? rising?on the metal? )
• Temperature change (touch the outside of the well/tube)
• Precipitate forming in solution vs.

Step 4: Write balanced equations while it's fresh

Don't wait until report-writing night. For each combination that reacted, write the molecular, complete ionic, and net ionic equations now. Identify oxidation states. Label oxidation and reduction half-reactions. The pattern — metal goes from 0 to +n, cation goes from +n to 0 — will repeat. Catching it in real time cements it.

Step 5: Rank the metals

Once you have all observations, order the tested metals from most to least reactive based on your* data. Not the textbook. If your results say lead is more reactive than zinc, write that down and flag it in discussion. On top of that, your data. Unexpected results are the interesting ones.

Common Mistakes (and How They Show Up in Reports)

Confusing "no reaction" with "slow reaction"

Students write "NR" after 30 seconds. The TA comes by at 20 minutes and sees copper plating on a lead strip. The report says no reaction. Which means the TA sees reaction. Credibility drops.

Fix: Record time intervals. Practically speaking, write "no visible change at 2 min; faint gray deposit at 15 min. " That's data. "NR" is a conclusion, and a premature one.

Mixing up which species is which

In the net ionic equation for Zn(s) + Cu²⁺(aq) → Zn²⁺(aq) + Cu(s), students sometimes write Zn²⁺ as a reactant. In practice, or forget the states. Or balance charge wrong. This is basic, but it happens constantly because the pattern feels repetitive and attention drifts.

For more on this topic, read our article on 65 inches in feet and inches or check out what percent of 12 is 8.

Fix: Do the first two or three slowly. Because of that, check oxidation states. In real terms, verify charge balance. Then the rest go faster — but still check each one.

Writing observations as conclusions

"Copper is less reactive than silver" is not an observation. Consider this: "Silver crystals formed on copper wire; solution changed from colorless to pale blue" is an observation. The first belongs in discussion. The second belongs in data.

Reports that blur this line read like the student doesn't know the difference between seeing and interpreting. TAs notice.

Ignoring the hydrogen tests

If your version includes Mg, Zn, Fe, Cu in HCl — or

Ignoring the hydrogen tests

If your version includes Mg, Zn, Fe, Cu in HCl (or H₂SO₄), the appearance of bubbles is a quick sanity check. But always note the rate* and location* of the bubbles—on the metal, at the interface, or rising from the solution. Which means a vigorous, continuous stream of gas right from the metal surface tells you the metal is definitely displacing hydrogen from the acid Mats, whereas a faint, intermittent hiss may indicate a sluggish reaction or that the acid is partially neutralised by the metal oxide already present. This small observation can later explain a seemingly “no‑reaction” result in the metal‑ion tests.

6. Writing the report: structure that sells the data

How to keep the narrative tight

1. Observation → Data → Interpretation
   Every sentence in the Results* section should be a direct transcription of what you saw. Use past tense, e.g., “The copper wire turned dark brown after 12 min.”
   In the Discussion* you transition to interpreting: “The discoloration indicates Cu²⁺ reduction.”

2. Avoid filler
   “It was observed that…” is redundant. Just state the observation.
   “The reaction was rapid” is vague; specify shit: “It produced a vigorous stream of H₂ within 15 s.”

3. Use the same symbols
   If you write “Cu²⁺” in the equations, keep it consistent. Avoid “copper ion” in one place and “Cu²⁺” in another.

4. Quantify when possible
   If you measured the temperature change, give the °C value. If you timed the reaction, give minutes. Numbers make the data concrete.

7. Common pitfalls in the write‑up* and how to dodge them

8. Final checklist before turning it in

• [ ] All observations recorded in the lab notebook before* the report is drafted.
• [ ] Balanced equations (molecular, complete ionic, net ionic) for every reaction that occurred.
• [ ] Oxidation states clearly labelled.
• [ ] A clear, data‑driven ranking of the metals.
• [ ] A paragraph explaining any deviations from the textbook series.
• [ ] All figures, tables, and photographs properly labelled and referenced.
• [ ] No new data or calculations introduced in the discussion or conclusion.
• [ ] The report is 4–6 pages, double‑spaced, 12‑point Times New Roman or equivalent.

Conclusion

A well‑written metal‑reactivity report is less about memorising the reactivity series and more about turning raw, sometimes messy, observations into a coherent narrative that demonstrates your grasp of redox chemistry. By acting as a scientist—recording, analysing, and interpreting—

rather than just a student following a recipe—you transform a routine laboratory exercise into a rigorous scientific investigation. Which means mastering these reporting techniques ensures that your experimental findings are not merely a collection of disconnected facts, but a structured argument that validates the underlying principles of electrochemistry. The bottom line: the ability to communicate your results with precision, clarity, and mathematical accuracy is what distinguishes a competent chemist from a casual observer.