Hydrogen peroxide, H2O2, is unstable, especially when in high concentrations. It breaks down into water and oxygen.
But manganese(IV) oxide, also known as manganese dioxide, catalyses the decomposition, which means that it speeds up the decomposition of the hydrogen peroxide. Although decomposition of hydrogen peroxide also happens naturally, it is very slow. So manganese(IV) oxide can be added to speed things up.
Here is the reaction equation:
Hydrogen peroxide → Water + Oxygen
2 H2O2 → 2 H2O + O2
Reaction by YOSF
Tuesday, February 8, 2011
Sunday, February 6, 2011
Reaction #9 - Dehydration of sucrose
Dear readers,
In this post, I shall show you how to dehydrate sucrose (or table sugar).
Pure sulfuric acid, or H2SO4, is very hydrophilic, which means it is attracted to water molecules. In other words, it absorbs a lot of water.
On the other hand, sucrose has a chemical formula of C12H22O11, which can also be "split" into C12 and H22O11. H22O11 is "equivalent" to 11 H2O, so when the sulfuric acid "absorbs" these "water" from the sucrose, only carbon is left.
Therefore, if you mix high purity sulfuric acid with sucrose, you will get a black mass of carbon left.
Hope you enjoyed reading it!
Video that demonstrates this experiment (and further talks about sulfuric acid):
This video contains Portugese subtitles (but English audio), so you can click the "CC" in the video and click Translate and choose English. It give you roughly the meaning of what the person (people) is/are saying.
In this post, I shall show you how to dehydrate sucrose (or table sugar).
Pure sulfuric acid, or H2SO4, is very hydrophilic, which means it is attracted to water molecules. In other words, it absorbs a lot of water.
On the other hand, sucrose has a chemical formula of C12H22O11, which can also be "split" into C12 and H22O11. H22O11 is "equivalent" to 11 H2O, so when the sulfuric acid "absorbs" these "water" from the sucrose, only carbon is left.
Therefore, if you mix high purity sulfuric acid with sucrose, you will get a black mass of carbon left.
Hope you enjoyed reading it!
Reaction by YOSF
Video that demonstrates this experiment (and further talks about sulfuric acid):
This video contains Portugese subtitles (but English audio), so you can click the "CC" in the video and click Translate and choose English. It give you roughly the meaning of what the person (people) is/are saying.
Notice - Renaming of Chemistry Blog
IMPORTANT NOTICE
On 4 Feb 2011, 1:08 pm GMT, the GITS & YOSF Company's Chemistry Theories blog has been changed to GITS and YOSF Company's Chemistry Blog.
The URL has also been changed from gyc-chemistrytheories.blogspot.com to gyc-chemistryblog.blogspot.com.
On 4 Feb 2011, 1:08 pm GMT, the GITS & YOSF Company's Chemistry Theories blog has been changed to GITS and YOSF Company's Chemistry Blog.
The URL has also been changed from gyc-chemistrytheories.blogspot.com to gyc-chemistryblog.blogspot.com.
Saturday, February 5, 2011
Reaction #8 - Aluminium with acid and alkali
Aluminium is amphoteric, which means it reacts with both acid and alkali to form other compounds.
Let's take this example:
Acid:
Aluminium + Nitric acid → Aluminium nitrate + Hydrogen
2 Al + 6 HNO3 → 2 Al2(NO3)3 + 3 H2
Alkali:
Aluminium + Sodium hydroxide + Water → Sodium aluminate + Hydrogen
2 Al + 2 NaOH + 2 H2O → 2 NaAlO2 + 3 H2
Hope you've enjoyed reading it!
Let's take this example:
Acid:
Aluminium + Nitric acid → Aluminium nitrate + Hydrogen
2 Al + 6 HNO3 → 2 Al2(NO3)3 + 3 H2
Alkali:
Aluminium + Sodium hydroxide + Water → Sodium aluminate + Hydrogen
2 Al + 2 NaOH + 2 H2O → 2 NaAlO2 + 3 H2
Hope you've enjoyed reading it!
Friday, February 4, 2011
Reaction #7 - Alka-Seltzer tablet
I'm sure all of you have heard about the effervescence of an Alka-Seltzer tablet (an antacid) when it is placed in water. But do you know how it works?
Well, here is the answer: The Alka-Seltzer tablet contains sodium bicarbonate (and a little bit of potassium bicarbonate) and anhydrous citric acid. In solid forms, the chemicals do not react. But once they are dissolved, they react vigorously:
C6H8O7 (aq) + 3 NaHCO3 (aq) → Na3C6H5O7 (aq) + 3 H2O (l) + 3 CO2 (g)
Citric acid + Sodium bicarbonate → Sodium citrate + Water + Carbon dioxide
Thus, the carbon dioxide gas bubbles out of the solution.
Reaction by YOSF
Well, here is the answer: The Alka-Seltzer tablet contains sodium bicarbonate (and a little bit of potassium bicarbonate) and anhydrous citric acid. In solid forms, the chemicals do not react. But once they are dissolved, they react vigorously:
C6H8O7 (aq) + 3 NaHCO3 (aq) → Na3C6H5O7 (aq) + 3 H2O (l) + 3 CO2 (g)
Citric acid + Sodium bicarbonate → Sodium citrate + Water + Carbon dioxide
Thus, the carbon dioxide gas bubbles out of the solution.
Reaction by YOSF
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