0923A

Our trip to Science Centre lets us understand more about the fantastic experiments that revolves around Chemistry. The experiments shown to us consist of the invisible ink, elephant toothpaste, silver mirror, dragon fire, super absorbent polymer and many more. The experiment which impresses us is the Invisible Ink.
DIY Invisible Ink
• Use the juice of an orange/ lemon to write some words
• Use a warm iron to heat up the paper
• The words written in the juice can now be seen
Reactants used: Potassium thiocyanate[KSCN] & Ferric chloride[FeCl3]

Equation:
KSCN(aq) + FeCl3(aq) -> [Fe (SCN)]^2+(aq)
Colourless Brick red light red

Applications
1) Making an Invisible Ink Pen
• Pour lemon juice into your ink well or small bowl. Vinegar also works as a less effective alternative.
• Try a cotton swab, a toothpick, fountain pen, or calligraphy pen. Dip it into the invisible ink.
Write your message.
• Draw a map to your secret treasure, write a love letter, or put the combination to your vault on the back of your business card.
• Allow the ink to dry. As the ink dries your message will disappear.
• To reveal your secret message. Heat the invisible ink to reveal your message.
• Try holding your message over a light bulb, ironing the message, placing it on a cookie sheet in a hot oven for a few minutes or holding it around 4 inches above a flame. The ink will allow the written message to burn faster than the paper, turning your secret message brown.
• Stop heating before your paper scorches.

How To Make Invisible Ink For Secret Spy Messages DIY - The most amazing bloopers are here
2) Making an Invisible Ink printer
Lemon juice has been used as invisible ink for centuries thus; messages written in lemon juice are invisible to the naked eye. However, when brushed with a mix of iodine and water, they become quite visible. An updated version of this technique is by modifying an
HP ink cartridge so that it prints in lemon juice instead of ink.


Fill a Used Print Cartridge with Invisible Ink - video powered by Metacafe
Other Invisible Inks
• Phenolphthalein, commonly used as a pH indicator, turns pink in the presence of a base such as ammonia fumes or sodium carbonate.
• Vinegar, is revealed by red cabbage water. Vinegar contains acetic acid that affects the pH indicator in red cabbage water. Vinegar may also be developed by heat, as above.
• Ammonia, developed by red cabbage water.
• Copper sulfate, developed by sodium iodide, sodium carbonate ammonium hydroxide or potassium ferricyanide.
• Lead(II) nitrate, developed by sodium iodide.
• Iron sulfate, developed by sodium carbonate or potassium ferricyanate.
• Cobalt chloride, developed by potassium ferricyanide.
• Iron sulfate, developed by sodium sulfide.
• Starch, developed by iodine solution which turns starch dark blue and the paper light blue.
• Lemon juice, developed by iodine solution (ink turns white, paper turns light blue).
• Sodium chloride (common table salt), developed by silver nitrate.

Done by: Lan, Melissa, Huong ,Theora, Yong Bang (0923A)

0912A

This Science Center trip was indeed an enriching one as we got to see the different Amazing Chemistry Experiments, which were

1. The Invisible Ink
2. Think Ink
3. Light Stick
4. Elephant Toothpaste
5. Silver Mirror
6. Genie In The Bottle
7. Super Absorbent Polymer
8. Dragon Fire
9. Cloth Burning
10. Blue Bottle Experiment

These experiments had shown us how Chemistry is closely related to our daily life and the amazing things brought about by the reaction between the different chemicals.

The experiment that impressed me the most were the Silver Mirror and the Super Absorbent Polymer while the most interesting experiment was the light stick.

Silver Mirror

Chemicals needed :

1. Silver Nitrate
2. Potassium Hydroxide
3. Glucose (dextrose)
4. Ammonia solution
5. Nitric Acid
6. Water

The "mirror" was formed because of redox reaction.

Overall equation:

CH3CH2CHO(aq) + 2[Ag(NH3)2]+(aq) + 3OH-(aq) → 2Ag(s) + CH3CH2COO-(aq) + 4NH3(aq) + 2H2O(l)

Video:

Super Absorbent Polymer

It can absorb and retain extremely large amounts of a liquid relative to its own mass (about 500 times its mass). It absorb aqueous solutions through hydrogen bonding with the water molecule. However, when put into a 0.9% saline solution, the absorbency drops to maybe 50 times its weight as the presence of valent cations in the solution will impede the polymers ability to bond with the water molecule.

Some of its uses include Diapers and Medical waste solidification.

Let the video shows how it works

Elephant toothpaste

Hydrogen peroxide (H2O2) decomposes into water and oxygen gas, but normally the reaction is so slow as to be imperceptible.

2H2O22H2O + O2 (G)

What happens when you pour hydrogen peroxide onto a cut? It bubbles! That's because there is something in your bodily fluids that catalyzes the reaction. A catalyst is a substance that speeds up a reaction, without being consumed itself.

In this demonstration we use a 30% hydrogen peroxide solution, which is much more concentrated than the 3% solution you can buy in the store. The production of oxygen gas is made more noticeable by adding some dish soap, which makes the foam. The reaction is catalyzed by iodide ion (I-) from potassium iodide. The iodide ion changes the mechanism, or pathway, by which the reaction occurs. In the first step of a two step process, iodide ion reacts with hydrogen peroxide to form water and the hypoiodite ion (IO-). This hypoiodite ion reacts with another molecule of hydrogen peroxide, giving water, oxygen, and iodide ion.

Notice that the iodide ion is regenerated, allowing it to go back and react with another molecule of hydrogen peroxide. This can continue for thousands of cycles. Note, too, that if one adds these two steps together, the I- and OI- cancel out, giving the same net reaction as above. The iodide is neither produced nor consumed in the reaction, but it changes the reaction mechanism, causing it to go faster. The rapid production of bubbles of oxygen gas, along with the dish soap, quickly creates a large quantity of foam.

Light Stick

It Contain :
1. Hydrogen peroxide solution
2. A solution containing a phenyl oxalate ester
3. Fluorescent dye.

This is what happen within the light stick :
1. The hydrogen peroxide which is the activator oxidises the phenyl oxalate ester, resulting in a chemical called phenol and an unstable peroxyacid ester.
2. The unstable peroxyacid ester decomposes, resulting in additional phenol and a cyclic peroxy compound.
3. The cyclic peroxy compound decomposes to carbon dioxide.
4. This decomposition releases energy to the dye.
5. The electrons in the dye atoms jump to a higher level, then fall back down, releasing energy in the form of light.

That's all about it.

Chemistry Mini Competition

Hello teachers!Tse Chun Kit,Rohan and Wilson are here to own this Mini Chemistry competition. Honestly,we do not know what's the purpose of this competition other than testing our understanding on the enrichment programme.But since we are....chosen.. to participate in this competition, sooo HERE WE ARE=D

Firstly, we just have to comment that the enrichment programme lecturer did a great commendable marvellous wonderful excellent superbly splendid job in educating us with various different unfamiliar chemistry experiments,venturing with us into a new ground of chemistry.

Lets start the ball rolling with the first experiment.

1.Invisible Ink

This experiment takes place by reacting:
Potassium thiocyanate[KSCN] and Ferric chloride[FeCl3]

Equation:
KSCN(aq) + FeCl3(aq) -> [Fe (SCN)]^2+(aq)
colourless Brick red light red

When the lecturer added Ferric Chloride onto the piece of paper she had earlier prepared,
FeCl3 reacts with the KSCN to form Fe[(SCN)]^+2 solution which is visible to us.
and the WELCOME word slowly surfaced

Everyone was like.."WOAHHH"
and of course.."Awwwwwww.."

This is somehow similar to how Magic Pens work.You know those type you use when you are young,and you go" MUMMY..see..i know magic.i colour white on blue and i get yellow".It's all about chemistry reactions.So pleaseee..come back to Earth

See how the colour change in this video!



2.Think Ink

This is an experiment which react 2 colour reactants together
and after a couple of seconds, it turns dark blue

Searching more of the Internet, it shows how this works.

First, the iodate reacts with the bisulfite:
1) KIO3(aq) + 3 NaHSO3(aq) ---> KI(aq) + 3 NaHSO4(aq)

It can be written as
IO3-(aq) + 3 HSO3(aq)----> I-(aq) + 3 SO42-(aq) + 3 H+(aq)

Some formed iodide reacts with more iodate to get iodine (I2)

2) 5 I-(aq) + IO3- (aq)+ 6 H+(aq) ---> 3 I2(aq) + 3 H2O(l)

However, iodine will not react with starch as long as bisulfite is present. The reaction with starch is slower than the reaction with bisulfite. So the iodine will react with bisulfite to form more sulfate, until there is no more bisulfite.

3) I2(aq) + HSO3-(aq) + H2O(l) ---> 2 I-(aq) + SO42-(aq) + 3 H+(aq)
when there is no more bisulfite, I2 produced in (2) will then complex with the starch.

4) I2(aq) + starch(aq) ---> iodine-starch complex (blue-black)

CHIM uh..
Basically, when we were at the lecture hall, we were stunned by the result cause i think practically no one(except for teachers maybe) expected that.This experiment is cool man.
Noo doubt.

This's how the experiment goes..WATCH THIS(till 0:30)=D


3.Light Stick

Ah ha!This is my favourite..I never knew how light stick works until now-_-
So there..


The glow is the result of 2 chemicals mixing together.
1.Hydrogen Peroxide(H2O2)
2.Phenyl Oxalate Ester and Fluorescent Dye solution(C14H10O4.)

When we bend the light stick, we break the glass vial in the casing that contain the Hydrogen Peroxide solution.The H2O2 is released into the plastic casing where it reacts with the Phenyl Oxalate Ester and Fluorescent Dye solution.Then TADA..glowing stick.

Equation: cyalume + H2O2 + dye → trichlorophenol + 2CO2 + dye[♦]

watch this glow stick experiment!



4.Blue Bottle Experiment

This is the experiment of the blue solution.A bottle half-full of a colorless liquid is shaken and turns blue. On standing undisturbed, the blue color fades. The cycle may be repeated several times. Other colors can be produced by substituting other indicators for the methylene blue commonly used.

HA!WHY!?

Firstly,
Glucose (alkaline) + Methylene Blue(blue)--> Methylene White(colourless) [When shaked]
Methylene White -> Methylene Blue + O2 [when left untouched for couple of seconds]

It happens when shakened,Methylene Blue reacts with O2 in the flaska and get oxidised to become Methylene White.
When left undisturbed, Methylene Blue reduce to give back Methylene White(colourless) and O2

Here's a video



5.Cloth burning

If i were 6 instead of 16, i might be more surprised.
How can you burn a cloth without getting ashes as remains?
Science again.

Firstly, the cloth is soaked with 50% water and 50% alcohol.
It is soaked in the water first,then alcohol.
When the fire is ignited, the fire burns the alcohol instead of the cloth.
The water acts as a protection against the fire,which prevented the cloth from being turning into ashes.

Cant find any video on that.
But after researching on the Internet, people say this experiment is still dangerous as although the fire doesnt burn the cloth,it is still a real fire after all! duh right..

So must handle with care after all

6. Silver Mirror Reaction
Ionic Equation:
CH2OH(HOH)4CHO(aq) + 2(Ag(NH3)2)^+(aq) + 30H^-(aq) -> 2Ag(aq) + CH2OH(CHOH)4COO^-(aq) + 4NH3(g) + 2H2o(l)

Tollens’ reagent is a solution of silver nitrate, ammonia, and potassium hydroxide which produces a silver diamine complex [Ag(NH3)2]+. The solution is added with a sample of an aldehyde,mixed and shaken.The silver oxidises the aldehyde to a carboxylic acid which result in the silver to be reduced to elemental silver.This production of elemental silver slowly coats the flask with a thin layer of silver.

It was amazing when we see how the lecturer took the the big clear flask with the solution inside and turn it into a silver coated flask which is as reflective as a mirror.
I was stunned.Definitely.I didnt expect that.






bi ba pa ba bi ba pa ba bi pa ba pa pa bi ba..

7.Super Absorbent Polymer aka SAP aka(slush powder)

Absorb water to form Gel
Add salt to turn it back into liquid state.(reversible reaction)

SAP may absorb 500 times its weight (from 30-60 times its own volume), but when put into a 0.9% saline solution, the absorbency drops to maybe 50 times its weight.

Made up of:
-polymerization of acrylic acid blended with sodium hydroxide in the presence of an intiator to form a poly-acrylic acid
-sodium salt(sometimes referred to as cross-linked sodium polyacrylate)

used in
-candles
-diapers
-surgical pads and more..

video



Maybe this is a good idea for Bladder Buddy..

8.Genie in the Bottle

Equation: 2H2O2(aq)-----> 2H2O(g) + O2(g)
MnO2
(Manganese
Dioxide) as catalyst

When MnO2,a catalyst, is added into H2O2 in a bottle,a "mist" is seen.The "mist" we see is dense water vapour.

The reaction is EXOTHERMIC!the bottle gets a bit warmer after the reaction.

Bottle may shrink because of this reaction.(depend on what bottle used)


Genie In A Bottle Experiment - Funny home videos are a click away

9.Elephant Toothpaste

What is needed:

-30% Hydrogen Peroxide solution(stronger than average H2O2 and not available in stores)
-Detergent
-Manganese Dioxide(Catalyst)
-Colouring(optional)

How it works

Manganese Dioxide speed up the decomposition of Hydrogen Peroxide

2H2O2 --> 2H2O + O2(g)

Dishwashing detergent captures the oxygen that is released, making foam.

Add colouring to spice up the experiment.

Because of the fast decomposition, the foam formed in the tube expands so quickly and oozes out in large amount.Resembling Elephant toothpaste.

VIDEOOoo




10.Dragon Fire aka Fine Dust Explosion

Make use of Lycopodium powder, obtain from Lycopodium which is a genus of clubmosses, also known as ground pines.

-The powder is highly flammable.
-When blown toward a fire source, the fire emerged resemble fire blown out of the dragon mouth like the one you see in Shrek movie.

Lycopodium powder used in
-fireworks
-photographic flash powder
-fingerprint powders

Foooshhh



There you have it.This is our blog entry for this competition!
0911D owning chemistry..;D
Yawns..Time for bed-_-

Hey all you yandaos and chiobus out there!!!

Still a virgin to chemistry? Or thinking chemistry is only titration ? NaCl ? HCl??

You totally wrong! But fear not ! 0912D saviors is here !!!

Here we go now!!

Lets start off with some pic!!

Cool hot pink colour , its from chemical found in the internal of a lightstick

Lightsticks

How a glowstick works.

1. Plastic casing covers the inner fluid. which can glow (kn)

2. Glass vial covers the solution.

3. Phenyl Oxalate and fluorescent dye solution.

4. Hydrogen Peroxide solution.

5. After the glass vial is broken and the solutions mix, the glowstick glows.

Sliver mirro experiment !
MY very own disco ball !! Lets go disco!!
Actually is a coating of silver on the inside give the shiny look!

Beverages LOOK SO REAL!! But too bad can’t drink T_T

It is actually made form this “magic water” , which is made up of Potassium Hydroxide
and Potassium Ferric(II) Cyanide solutions. The colour is due to precipitate when adding some reagent.

Elephant toothpaste

Mix two solutions together and you get an amazing eruption of oxygen filled foam that looks like a giant stream of toothpaste. Or elephant toothpaste.

This due to the reaction of Hyrodgen peroxide using catalyse manganese dioxide. Oxygen is given off and cause the detergent to bubble and giving a stream of toothpaste like stuff.

Dragon Fire : Lycopodium (ground pine/club moss)
-Used in fireworks, pyro technique . Give fiery fire look! COOLEST OF ALL !!

How cool would it be if we can breath fire !!!!

Superabsorbent polymers (SAP) (also called slush powder) are polymers that can absorb and retain extremely large amounts of a liquid relative to its own mass. Water absorbing polymers, classified as hydrogels, absorb aqueous solutions through hydrogen bonding with the water molecule.

Did you know that SAP is found in ur diaper ? COOL chem is everywhere! Even the unimaginable !!


So What have we learn today Yandaos and chiobus?
CHEMISTRY IS EVERYWHERE !!
Chem is everyday of ur life and
Most importantly CHEMISTRY IS FUN

I hope that this will tweak you to love chem !!
CAUSE 0912 D loves chemistry!!! KUDOS to chemistry lover and teachers !!!


Done by : Alvin ang / Maria Hani / Richard Yeo / Billy Musa /Karthi / timothy /Guang jin and yewei.