June 2012
174 posts
hey, Allan and Ramiro. I just wanted to say that you guys run an awesome chemistry blog.
Thank you, Anon.
I recall that nitroglycerine was first suggested for medical use after factory workers complained of faintness and other symptoms of low blood pressure.
I do not doubt that stories of factory workers with low blood pressure are true and upon research it appears that even Alfred Nobel himself complained of getting headaches from it; however, even this alone would not warrant nitroglycerin, or any compound for that matter, to be used medicinally. Dr. Murrell’s studies and subsequent publishing within a medical paper is what really prompted the medical community to take notice and adopt its usage.
Err, who the hell decided nitroglycerin was a good thin to give patients?!
Dr. William Murrell, that’s who.
Following the discovery that amyl nitrite helped alleviate chest pain, Dr. Murrell experimented with the use of nitroglycerin to alleviate angina pectoris and to reduce the blood pressure. He began treating his patients with small doses of nitroglycerin in 1878, to great success. This treatment was soon adopted into widespread use after Murrell published his results in the journal The Lancet in 1879.
The medical establishment used the name “glyceryl trinitrate” or “trinitrin” to avoid alarming patients who associated nitroglycerin with explosions and you, my friend, are a perfect example of why they might have done this, hahaha.
Who is your favorite chemist?
Pharaoh's Serpent: The Reaction of Mercury (II) Thiocyanate
Pharaoh’s serpents, or pharaoh’s snakes,are a type of small firework in which a lighted tablet exudes smoke and ash in a growing column which resembles a serpent. They are toxic so now this firework is only produced as a chemistry demonstration. The reaction is a result of the combustion of mercury (II) thiocyanate (Hg(SCN)2).
Igniting mercury(II) thiocyanate causes it to decompose into an insoluble brown mass that is primarily carbon nitride, C3N4. Mercury(II) sulfide and carbon disulfide are also produced.
2Hg(SCN)2 → 2HgS + CS2 + C3N4
Flammable carbon disulfide combusts to carbon(IV) oxide and sulfur(IV) oxide:
CS2 + 3O2 → CO2 + 2SO2
The heated C3N4 partially breaks down to form nitrogen gas and dicyan:
2C3N4 → 3(CN)2 + N2
Mercury(II) sulfide reacts with oxygen to form mercury vapor and sulfur dioxide. If the reaction is performed inside a container, you will be able to observe a gray mercury film coating its interior surface.
HgS + O2 → Hg + SO2
Rapid decomposition of Hydrogen Peroxide catalyzed by Potassium Iodide
2 H2O2 → 2 H2O + O2
This is called reaction is often called Elephant’s Toothpaste and is a pretty simple experiment to set up. Be careful though, it’s an exothermic reaction, and concentrated hydrogen peroxide can bleach clothing and cause burns to the skin. Unlike the individuals in this .gif, please wear eye protection.
