Potassium Permanganate And Glycerin: Difference between revisions
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== | {| class="wikitable" style="color:black; background-color:#ddd; margin-left: auto; float:right" | ||
| [[Chemistry]]: | |||
| Rate of Reaction, Redox Reactions | |||
|- | |||
| Grade Range: | |||
| [[Elementary School]], [[Middle School]], [[High School]] | |||
|- | |||
| Format: | |||
| [[Stage]] | |||
|} | |||
This demonstration produces smoke and fire, so be sure to check with the school or event coordinator if smoke and fire are OK before bringing this demonstration. Students of all ages will enjoy seeing this demonstration in action, but don't let them get close to it. Be sure to practice the timing of the '''Primary''' style before presenting this demonstration. | |||
== | == Materials == | ||
* Potassium Permanganate | |||
* Glycerin or Glycerol | |||
* Scoopula | |||
;Primary Presentation: | |||
* Eyedropper | |||
* Cork Base | |||
* Large Watch Glass or Small Metal Bowl | |||
;Alternative Presentation: | |||
* Two Eyedroppers | |||
* Metal Stand Base | |||
* Two Medium Watch Glasses | |||
== | == Safety Precautions == | ||
Please read the Fire Demonstration section of the [[Demonstration Safety]] page before performing this demonstration. Potassium Permanganate is toxic if ingested and can oxidize tissue, so avoid direct contact with the powder. After the reaction completes, it can be safely washed down a drain, but continue to wear gloves in case of any non-reacted powder. | |||
This demonstration requires: safety glasses, rubber or nylon gloves, blast shield | |||
== Demonstration == | |||
;Primary Presentation: | |||
# Set the watch glass or bowl on the cork base, and have the blast shield in front of it. Use the scoopula to put a small pile of potassium permanaganate (KMnO<sub>4</sub>) in the middle of the dish, and make a small indentation in the center of the pile. | |||
# Explain what KMnO<sub>4</sub> is to the audience, and introduce redox reactions. Ask students for ideas on what they think will happen when you add the glycerin/glycerol to the bowl. | |||
# The next part of this demonstration requires careful timing. Put a small drop of the glycerin/glycerol into the dish, in the indentation of the pile. Immediately go into the following explanation: | |||
#* "When KMnO<sub>4</sub> mixes with glycerin/glycerol, a redox reaction starts. This reaction starts out really slow, but produces a lot of heat, so it will start to speed up bit by bit. As the KMnO<sub>4</sub> oxidizes the sugar, it will speed up more and more until it finally starts to smoke, and after that it will ignite!" | |||
#* The reaction takes 10-15 seconds to ignite, depending on outside temperature and the temperature of the glycerin/glycerol. If timed carefully, the reaction will start smoking when you say "until it finally starts to smoke", and then ignite 1-2 seconds later! | |||
# After applause, ask students if they can guess why it starts slowly. For an older audience, you can use a whiteboard to draw the reaction, and point out the large amount of KMnO<sub>4</sub> needed to start the reaction. | |||
;Alternate Presentation: | |||
# Set the two watch glasses next to each other on the metal stand base, and have the blast shield in front of it. Use the scoopula to put a small pile of potassium permanaganate (KMnO<sub>4</sub>) in the middle of each, and make a small indentation in the center of one pile. | |||
# Explain what KMnO<sub>4</sub> is to the audience. Ask students for ideas on what they think will happen when you add the glycerin/glycerol. Also ask if they think ''where'' you put the sugar will affect how fast it goes. | |||
# Put a small drop of the glycerin/glycerol into each dish. In the untouched dish, put the drop on the side of the mound, with it only partially touching the powder. In the dish with the indentation, put the drop in the center. Do this step quickly! | |||
# Ask the audience to vote on which one they think will ignite first. As you do this, the one with the indent will start smoking, and then ignite! the other will do the same, but after the first is already lit. | |||
# After applause, ask students why the placement of the sugar affects the rate of reaction. Discuss. | |||
== Why This Works == | |||
Potassium Permanganate | ===Short Explanation=== | ||
Reduction-Oxidation Reactions, or ''Redox Reactions'', are reactions that involve a transfer of electrons. ''Oxidizers'' such as Potassium Permanganate (KMnO<sub>4</sub>) take electrons, while ''Reducers'' such as Glycerin and Glycerol give electrons. This means that our glycerin/glycerol is ''Oxidized'', or loss electrons, and our KMnO<sub>4</sub> is ''Reduced'', or has gained electrons. An easy way to remember this is "'''LEO''' says '''GER'''", where '''LEO''' means '''L'''oss '''E'''quals '''O'''xidation and '''GER''' means '''G'''ain '''E'''quals '''R'''eduction. | |||
In both styles for this reaction, we see that it takes a little while for it to start. This is because the ''Rate of Reaction'', or how quickly this reaction happens, relies heavily on the physical properties of the chemicals. This reaction needs to have a lot of the KMnO<sub>4</sub> powder in contact with the glycerin/glycerol in order to react. If there isn't enough of each in contact, then it reacts very slowly, like if the glycerin/glycerol is on the side of the pile. If there is a lot of each in contact, then it will react faster, like putting the glycerin/glycerol in the middle of the powder. This reaction also needs a lot of energy to start, but releases a lot of heat at the end. This is why the temperature of the reactants plays a big role on how fast it will react! | |||
===Full Explanation=== | |||
'''''COMING SOON''''' | |||
<!-- | |||
This is where you will explain the demonstration in full, and provide all additional information that pertains to the demo. Unlike the short explanation above, this should be worded so someone who is familiar with the topics might understand it. If needed, you can provide equations and citations for additional sources of information on the topic. This is also where you will find some answers for trickier questions, such as "How does a plane fly upside-down?" for the Bernoulli's Principle demo. If you want to add a floating box for equations, copy the following: | |||
== | {| class="wikitable" style="color:black; background-color:#ddd; text-align: center; margin: auto" | ||
| This will give you | |||
| a floating box. | |||
|- | |||
| The box will be | |||
| centered for you. | |||
|} | |||
--> | |||
== Additional Information == | |||
* This demonstration pairs well with the [[Elephant Toothpaste]] and the [[Shaking Solution]] demonstrations. | |||
* This demonstration is a part of the [[Fire and Ice Show]]. | |||
<!-- | |||
== What to Say == | == What to Say == | ||
| Line 60: | Line 98: | ||
The reaction in this demo was apparently used to start a fire once on the TV show Survivor Man, but it is not a common practice.(A lighter would probably be way more reliable and it won't turn your hands purple!) A forum discussing this: http://episteme.arstechnica.com/eve/forums/a/tpc/f/770002407831/m/857005467831 | The reaction in this demo was apparently used to start a fire once on the TV show Survivor Man, but it is not a common practice.(A lighter would probably be way more reliable and it won't turn your hands purple!) A forum discussing this: http://episteme.arstechnica.com/eve/forums/a/tpc/f/770002407831/m/857005467831 | ||
--> | |||
Revision as of 17:12, 26 September 2016
| Chemistry: | Rate of Reaction, Redox Reactions |
| Grade Range: | Elementary School, Middle School, High School |
| Format: | Stage |
This demonstration produces smoke and fire, so be sure to check with the school or event coordinator if smoke and fire are OK before bringing this demonstration. Students of all ages will enjoy seeing this demonstration in action, but don't let them get close to it. Be sure to practice the timing of the Primary style before presenting this demonstration.
Materials
- Potassium Permanganate
- Glycerin or Glycerol
- Scoopula
- Primary Presentation
- Eyedropper
- Cork Base
- Large Watch Glass or Small Metal Bowl
- Alternative Presentation
- Two Eyedroppers
- Metal Stand Base
- Two Medium Watch Glasses
Safety Precautions
Please read the Fire Demonstration section of the Demonstration Safety page before performing this demonstration. Potassium Permanganate is toxic if ingested and can oxidize tissue, so avoid direct contact with the powder. After the reaction completes, it can be safely washed down a drain, but continue to wear gloves in case of any non-reacted powder.
This demonstration requires: safety glasses, rubber or nylon gloves, blast shield
Demonstration
- Primary Presentation
- Set the watch glass or bowl on the cork base, and have the blast shield in front of it. Use the scoopula to put a small pile of potassium permanaganate (KMnO4) in the middle of the dish, and make a small indentation in the center of the pile.
- Explain what KMnO4 is to the audience, and introduce redox reactions. Ask students for ideas on what they think will happen when you add the glycerin/glycerol to the bowl.
- The next part of this demonstration requires careful timing. Put a small drop of the glycerin/glycerol into the dish, in the indentation of the pile. Immediately go into the following explanation:
- "When KMnO4 mixes with glycerin/glycerol, a redox reaction starts. This reaction starts out really slow, but produces a lot of heat, so it will start to speed up bit by bit. As the KMnO4 oxidizes the sugar, it will speed up more and more until it finally starts to smoke, and after that it will ignite!"
- The reaction takes 10-15 seconds to ignite, depending on outside temperature and the temperature of the glycerin/glycerol. If timed carefully, the reaction will start smoking when you say "until it finally starts to smoke", and then ignite 1-2 seconds later!
- After applause, ask students if they can guess why it starts slowly. For an older audience, you can use a whiteboard to draw the reaction, and point out the large amount of KMnO4 needed to start the reaction.
- Alternate Presentation
- Set the two watch glasses next to each other on the metal stand base, and have the blast shield in front of it. Use the scoopula to put a small pile of potassium permanaganate (KMnO4) in the middle of each, and make a small indentation in the center of one pile.
- Explain what KMnO4 is to the audience. Ask students for ideas on what they think will happen when you add the glycerin/glycerol. Also ask if they think where you put the sugar will affect how fast it goes.
- Put a small drop of the glycerin/glycerol into each dish. In the untouched dish, put the drop on the side of the mound, with it only partially touching the powder. In the dish with the indentation, put the drop in the center. Do this step quickly!
- Ask the audience to vote on which one they think will ignite first. As you do this, the one with the indent will start smoking, and then ignite! the other will do the same, but after the first is already lit.
- After applause, ask students why the placement of the sugar affects the rate of reaction. Discuss.
Why This Works
Short Explanation
Reduction-Oxidation Reactions, or Redox Reactions, are reactions that involve a transfer of electrons. Oxidizers such as Potassium Permanganate (KMnO4) take electrons, while Reducers such as Glycerin and Glycerol give electrons. This means that our glycerin/glycerol is Oxidized, or loss electrons, and our KMnO4 is Reduced, or has gained electrons. An easy way to remember this is "LEO says GER", where LEO means Loss Equals Oxidation and GER means Gain Equals Reduction.
In both styles for this reaction, we see that it takes a little while for it to start. This is because the Rate of Reaction, or how quickly this reaction happens, relies heavily on the physical properties of the chemicals. This reaction needs to have a lot of the KMnO4 powder in contact with the glycerin/glycerol in order to react. If there isn't enough of each in contact, then it reacts very slowly, like if the glycerin/glycerol is on the side of the pile. If there is a lot of each in contact, then it will react faster, like putting the glycerin/glycerol in the middle of the powder. This reaction also needs a lot of energy to start, but releases a lot of heat at the end. This is why the temperature of the reactants plays a big role on how fast it will react!
Full Explanation
COMING SOON
Additional Information
- This demonstration pairs well with the Elephant Toothpaste and the Shaking Solution demonstrations.
- This demonstration is a part of the Fire and Ice Show.