Universal Indicator with Dry Ice

This demonstration shows the color changes of universal indicator as a base is added to it and then that base is neutralized with carbonic acid (formed from dry ice). This demo is not filmed or taught very well because it was done as an extra during a lunch period because of a new state law that banned numerous chemicals and it looked like I was going to have to discontinue use of it, so I wanted to have a record of the demonstration.

Category:

Science & Technology

Tags:

• universal
• indicator
• carbonic
• acid
• base
• dry
• ice
• demo
• demonstration
• chem
• chemistry
• sully
• russia
• color
• colorful
• rainbow
• chemical

[Ben123planes]

add hydrochloric acid but no water with an alkali you can get loads of colours.

[mrericsully]

Yes, but the reaction is usually more violent, hot, and effervescent and this method gives me more time to talk to the students and interact with them.

[xXAUZZIEforLIFEXx]

very useful for my practical exam. Thank you

[mrericsully]

@LeJLaKaSaNDRa Search for an MSDS for it, I recommend Flinn Scientific's

flinnsci  (dot) com /Documents/MSDS/UV/UniversalIn­dicatorSol.pdf

[mrericsully]

@LeJLaKaSaNDRa Search for an MSDS for it, I recommend Flinn Scientific's flinnsci (dot) com /Documents/MSDS/UV/UniversalIn­dicatorSol.pdf

[infidile]

these highschool kids sound irritating

[Mrinny]

IndicatorS are not USUALLY green at pH 7... the universal indicator is!

[mrericsully]

In general, an indicator changes color because it absorbs (reacts with) some of the hydrogen ions (also viewed as protons) or releases some into the solution in an equilibrium reaction. Most indicators only go through two or three colors. A Universal Indicator is generally a mixture of of several indicators that have colors that work well together (for example one might be red in a base while another is blue and so the resulting color is purple) then as pH changes the color changes too.

[mrericsully]

I don't totally understand your question.

In terms of protons and neutrons they don't really enter into a chemical reaction and so I don't see why there would be any limit.

In terms of color changes it doesn't have to involve the transfer of electrons, but can involve instead the transfer of molecules (like OH-) depending on which acid-base definition/theory you trust.

[babycatmilker]

so for it to get its next color it could not have more than 4 electrons or it couldnt have more than 15 protons or neutrons? please answer me