STEM Series: Chemical Reactions II

STEM Series: Chemical Reactions II

Our STEM Series will focus on select biochemistry topics. Our videos are designed for high school-level students. Lecture instructors include UIC Urban Health Program pre-health students and UIC College of Medicine students.

ACCESS YouTube:
https://www.youtube.com/watch?v=4Gjm40pOKas

Embedded Links:
STEM Series: Chemical Reactions - Tie Dye with Bleach
https://www.youtube.com/watch?v=wfPkKe5lvbo&feature=emb_logo

STEM SERIES: Chemical Reactions - Tie Dye With Colored Dye
https://www.youtube.com/watch?v=xIRIsEQBobE&feature=emb_logo

How to Tie-Dye with Rit Dye
https://www.youtube.com/watch?time_continue=1&v=kktpGSe4Fx0&feature=emb_logo

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UIC Urban Health Club

May 28, 2020
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Transcript

  1. 1.

    UIC Urban Health Club - Spring 2020 STEM SERIES: CHEMICAL

    REACTIONS II Solubility and absorption chemical processes through the process of tie-dyeing
  2. 2.

    UIC Urban Health Club The Science of Tie-Dye STEM Series

    - Chemical Reactions: Solubility and absorption chemical processes through the process of tie-dyeing.
  3. 4.

    UIC Urban Health Club ❏ Tie-dyeing has been around for

    decades and is a fun, colorful way to decorate fabric. ❏ Tie-dye is a form of art and expression, but it also involves a lot of chemistry. ❏ Dye is a natural or synthetic substance used to apply color or to stain other materials, such as fabrics and fibers.
  4. 5.

    UIC Urban Health Club USEFUL TERMINOLOGY ABSORPTION: Process by which

    matter takes in another substance. The absorbed substance is spread throughout the absorbing matter, such as when a kitchen sponge soaks up water. SOLUTION: Homogeneous mixture in which one or more substances (the solutes) are dissolved into another substance (the solvent). Solutions are made up of elements or compounds mixed together at the molecular level. MIXTURE: Made of two or more substances that are combined physically. SOLUBILITY: Physical property that describes the ability of a chemical substance (the solute) to dissolve in a solvent to create a uniform solution. A substance that dissolves in another substance is soluble.
  5. 6.

    UIC Urban Health Club USEFUL TERMINOLOGY POLAR SUBSTANCES: Made up

    of particles that have an uneven distribution of electrons, creating a negative and a positive side. Generally, polar solutes will only dissolve in polar solvents. DIFFUSION: Movement of particles from an area of high concentration to an area of low concentration. NONPOLAR SUBSTANCES: Made up of particles that have an even distribution of electrons. The charges on the particles are neutralized. Nonpolar solutes generally only dissolve in nonpolar solvents. CHROMATOGRAPHY: Group of separation processes used to separate and analyze complex mixtures based on differences in their structure or composition. During chromatography, a mixture is moved over a stationary material, called the stationary phase. The mixture that flows over the material is called the MOBILE PHASE.
  6. 7.

    UIC Urban Health Club Experimental Procedure OBSERVE & RESEARCH ❏

    What materials do you observe? ❏ Predict how these materials may be used. ❏ Describe each stage (Absorption, Mixture, Solution, Solute, Solvent) PERFORM YOUR EXPERIMENT ANALYZE & CONCLUDE ❏ What happens when you add your solution (bleach, fabric dye)? ❏ Do any of the color spots have different colored edges? Is so, what colors? Why do you think this happened? (Polar substance, Nonpolar substance, Diffusion, Chromatography, Stationary phase, Mobile phase) ❏ Why do some of the colors separate into different colors? What is this separation process called?
  7. 8.

    UIC Urban Health Club Experiment #1: Tie-Dye with Bleach Key

    Findings ❏ Bleach contains sodium hypochlorite, which breaks chemical bonds and leads to a change in shape configuration of when it reacts with the chromophores found in clothing. ❏ Chromophores are chemical compounds that help us see a color by reflecting a certain portion of the visible spectrum of light. ❏ The change in shape configuration causes a change in the color that is reflected, as seen in the video.
  8. 9.

    UIC Urban Health Club Experiment #2: Tie-Dye with Fabric Dye

    Key Findings ❏ It is important to use 100% cotton or natural fiber fabrics. This is because synthetic materials will not bond to the dye molecules. ❏ A chemical reaction takes place between the dye molecules and the fabric molecules (dye bonds with the cotton). ❏ The dye molecules form covalent linkages when it diffuses from an aqueous solution into the hydrophilic fibers cotton fibers. ❏ The bond the dye creates with the fiber materials allows the dye to stay permanent even after washes.
  9. 11.

    UIC Urban Health Club As you perform the experiment, challenge

    yourself to identify the independent, dependent, and controlled variables, as well as whether there is a control setup for the experiment. (Hint: If you change the type of liquid [solvent], does the dye behave differently?) “You be the chemist” challenge