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Dehydration of Sugar (Black Foam)

  • Page ID
    128803
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    Required Training

    Required PPE

    UC Lab Safety Fundamentals

    Lab coat, safety glasses/goggles,

    nitrile gloves

    Equipment

    Chemicals

    150 mL beaker

    80 g sucrose

    Large catch pan

    20 mL conc. sulfuric acid

    Procedure:

    1. Pour 20 mL concentrated sulfuric acid on the sucrose in the tall beaker in a catch pan.
    2. The sucrose will dehydrate and form a large black column of black carbon-carbon dioxide foam.

    Discussion:

    This demonstration shows the dehydration of the organic molecule, sucrose. It follows the reactions below:

    C12H22O11 → 12 C + 11 H2O -919 kJ/mol

    C + O2 → CO2 -394 kJ/mol

    C12H22O11+ 12 O2 → 12 CO2 + 11H2O -5641 kJ/mol

    Hazards:

    Concentrated sulfuric acid is corrosive and may sputter out of the reaction vessel—always wear PPE and teat any spills with sodium bicarbonate or another suitable chemical before cleaning the area with water

    SOP:clipboard_ed3def11f660b2c79047325c9f2238c95.png

    Corrosive – Sulfuric Acid

    Disposal (by Storeroom)

    Return the beaker, catch pan, and any auxiliary waste created to the storeroom for proper neutralization and disposal.


    Dehydration of Sugar (Black Foam) is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by LibreTexts.

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