Coffee? Coffee. Coffee!!!!

*Ywan*
It's late, and you haven't finish your homework, and tomorrow you have to deliver a very important project and you haven't study for your Chemistry final exam!
You decided to make your self a nice hot cup of coffe to stay awake all night.
But how does it work? Before drinking your coffe you feel like half death, and after you are quite ready to run a marathon.




Well the reason of this is because coffe has caffein.
Caffeine (C8H10N4O2) is the common name for trimethylxanthine.

For the plants, caffeine acts as a natural pesticide. It paralyzes and kills insects that attempt to feed on the plants. The molecule was first isolated by the German chemist Friedrich Ferdinand Runge in 1819.
When purified, caffeine is an intensely bitter white powder. It is added to colas and other soft drinks to impart a pleasing bitter note. However, caffeine is also an addictive stimulant. In humans, it stimulates the central nervous system, heart rate, and respiration, has psychotropic (mood altering) properties, and acts as a mild diuretic.
Caffeine is believed to work by blocking adenosine receptors in the brain and other organs. This reduces the ability of adenosine to bind to the receptors, which would slow down cellular activity. The stimulated nerve cells release the hormone epinephrine (adrenaline), which increases heart rate, blood pressure, and blood flow to muscles, decreases blood flow to the skin and organs, and causes the liver to release glucose. Caffeine also increases levels of the neurotransmitter dopamine.



Caffeine is quickly and completely removed from the brain. Its effects are short-lived and it tends not to negatively affect concentration or higher brain functions. However, continued exposure to caffeine leads to developing a tolerance to it. Tolerance causes the body to become sensitized to to adenosine, so withdrawal causes blood pressure to drop, which can result in a headache and other symptoms. Too much caffeine can result in caffeine intoxication, which is characterized by nervousness, excitement, increased urination, insomnia, flushed face, cold hands/feet, intestinal complaints, and sometimes hallucinations.
The lethal ingested dose, for an adult person, is estimated to be 13-19 grams. While generally considered safe for people, caffeine can be very toxic to household pets, such as dogs, horses, or parrots. Caffeine intake has been demonstrated to reduce the risk of type II diabetes mellitus. In addition to use as a stimulant and flavoring agent, caffeine is included in many over-the-counter headache remedies.

A-TO-MIC MODELS

While various types of microscopes can reveal details at many levels of magnification, no microscope can produce images showing the detailed parts of single atoms. For understanding atoms at this level, we traditionally use models instead of actual images.

The models presented in this investigation show a highly simplified view of atoms, but they serve the purpose of allowing us to examine the number of protons, neutrons, and electrons in common elements.

Now a brief history of the first Atomic Models.

EARLY GREEK THEORIES


In 400 B.C., Democritus thought matter could not be divided indefinitely. And this led to the idea of atoms in a void.
In 350 B.C., Aristotle modified an earlier theory that matter was made of four “elements”: earth, fire, water, air. He was wrong, however, his theory persited for 2000 years.



JOHN DALTON

In the 1800's Dalton proposed a modern atomic modelbased on experimentation not on pure reason.

•All matter is made of atoms.
•Atoms of an element are identical.
•Each element has different atoms.
•Atoms of different elements combine in constant ratios to form compounds.
•Atoms are rearranged in reactions.

His ideas account for the law of conservation of mass (atoms are neither created nor destroyed) and the law of constant composition (elements combine in fixed ratios).



BOHR

•Electrons orbit the nucleus in “shells”
•Electrons can be bumped up to a higher shell if hit by an electron or a photon of light



There are 2 types of spectra: continuous spectra & line spectra. It’s when electrons fall back downthat they release a photon. These jumps down from “shell” to “shell” account for the line spectra seen in gas discharge tubes (through spectroscopes).

So...What are atoms?
Atoms are the basic building blocks of matter that make up everyday objects. A desk, the air, even you are made up of atoms!
There are 90 naturally occurring kinds of atoms. Scientists in labs have been able to make about 25 more.
Atoms are made of three basic particles:
Protons, which carry a positive charge.
Neutrons, which carry no charge.
*Protons and Neutrons are join together to form the nucleus, the central part of the atom*
Electrons, which carry a negative charge.

The nucleus of an atom is extremely small in comparison to the atom. If an atom was the size of the Houston Astrodome, then its nucleus would be the size of a pea.

"ATOMS ARE EVERYWHERE!!"

Alka Seltzer

Have you ever being in a big party? Or at least in a family reunion where they serve tons and ton of food? ...and obiously since it is all extremley delicious you can't stop eating. What happens next? Yeah... stomach ache and, if you had being drinking, a really bad head ache. But that isn't a big problem, the only thing you have to do is take an Alka-Seltzer and you'll feel like new! Why? What does the Alka Seltzer has that makes you feel like ready to party again?
Well here I'll leave you a really simple explanation of how the Chemistry of the Alka Seltzer works.


Alka Seltzer tablets contain solid sodium bicarbonate and citric acid. When dropped into water, sodium citrate, carbon dioxide, and water are formed.




The Carbon dioxide escapes in the form of bubbles, thats why it fizz. Leaving only water and and sodium citrate.


The sodium citrate is a weak base. It neutralizes stomach acid (mainly HCl).

Na3C3H5O7 (aq) + 3 HCl(aq) H3C3H5O7 (aq) + 3 NaCl(aq)