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Blue/Green

Short answer: When aluminum is added to copper sulfate solution with hydrochloric acid, the acid strips aluminum's oxide layer and aluminum displaces copper in a vigorous, heat-releasing reaction.

Copper compounds give flames a characteristic blue-green color, because heat excites copper's electrons, which emit specific wavelengths as they relax. The footage shows the reaction and a green flame.

VideoWrite-up2 sources
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What should you know about Blue/Green?

Quick facts. Each one stands alone and has a stable ID you can cite.

  1. Aluminum displaces copper.

    DD-361-F01 · Write-up · Exhibit A (Displacement)

  2. Acid removes aluminum's oxide.

    DD-361-F02 · Write-up · Exhibit B (Acid)

Video transcript: Blue/Green: Copper Compounds Turn a Flame Blue-Green

Did you know, when copper sulfate, hydrogen chloride and aluminum are combined, a fascinating reaction can occur, producing a distinctive blue or green flame. Here's how it works. Aluminum reacts with copper sulfate, causing a redox reaction, where aluminum displaces copper, releasing copper metal and aluminum sulfate. When hydrogen chloride is present, it can intensify this reaction, especially if the solution is heated. Copper ions from the copper sulfate then release a blue-green flame when burned, because of the unique way copper's electrons are excited by heat. NOW YOU KNOW!

Burned-in captions, read frame by frame (see transcript.md) · 28.1s Reel ·

Video coming soonBlue/Green · Instagram Reel
Blue/Green: Copper Compounds Turn a Flame Blue-Green Instagram Reel · · 28.1s

The write-up

Copper compounds turn a flame blue-green. Aluminum, copper sulfate and acid set it off.

  1. Exhibit A

    Displacement

    Aluminum displaces copper.

  2. Exhibit B

    Acid

    Acid removes aluminum's oxide.

  3. Exhibit C

    Color

    Copper gives blue-green flames.

  4. Exhibit D

    Electrons

    Excited electrons emit light.

  5. Exhibit E

    Heat

    The reaction releases heat.

Questions people ask about Blue/Green

Which metal colors the flame?

Blue-green.

Source: Write-up · Exhibit A (Displacement) · Wikipedia: Flame test

What displaces copper?

More reactive.

Source: Write-up · Exhibit B (Acid) · Wikipedia: Flame test

What does the acid remove?

Exposes metal.

Source: Write-up · Exhibit C (Color) · Wikipedia: Flame test

Why do flames get colors?

Emission.

Source: Write-up · Exhibit D (Electrons) · Wikipedia: Flame test

What test uses flame colors?

Identifies metals.

Source: Write-up · Exhibit E (Heat) · Wikipedia: Flame test

Test Your Knowledge

All quizzes →

5 questions, all from this case file. Answers are revealed instantly.

  1. Which metal colors the flame?

    1. Copper
    2. Sodium
    3. Lithium
    4. Iron
    Show the answer

    Answer: A. Copper Blue-green. Source: Write-up · Exhibit A (Displacement) · Wikipedia: Flame test

  2. What displaces copper?

    1. Aluminum
    2. Gold
    3. Neon
    4. Silver
    Show the answer

    Answer: A. Aluminum More reactive. Source: Write-up · Exhibit B (Acid) · Wikipedia: Flame test

  3. What does the acid remove?

    1. The oxide layer
    2. Copper
    3. Color
    4. Heat
    Show the answer

    Answer: A. The oxide layer Exposes metal. Source: Write-up · Exhibit C (Color) · Wikipedia: Flame test

  4. Why do flames get colors?

    1. Excited electrons emit light
    2. Dye
    3. Smoke
    4. Wind
    Show the answer

    Answer: A. Excited electrons emit light Emission. Source: Write-up · Exhibit D (Electrons) · Wikipedia: Flame test

  5. What test uses flame colors?

    1. Flame test
    2. Litmus test
    3. Turing test
    4. Blood test
    Show the answer

    Answer: A. Flame test Identifies metals. Source: Write-up · Exhibit E (Heat) · Wikipedia: Flame test

Cite this case file

Easterling, Marcus. "Blue/Green." The Detail Department (DetailEnjoyer), case file DD-361, last updated Nov 4, 2024. https://detailenjoyer.com/case/blue-green/

Permalink: https://detailenjoyer.com/case/blue-green/ · Last updated

Markdown version

Cite a single fact by its ID, for example DD-361-F01 → https://detailenjoyer.com/case/blue-green/#DD-361-F01