Reading Chemical Structures

Image result for chemical structure of caffeine

Take a look at the image above. This is the chemical structure of caffeine, a widely consumed chemical that you are probably familiar with (it's in your coffee). Scientists use this as a shorthand depiction of chemical structures. While this image may be confusing at first, it's actually very simple to understand once you know the rules! And there are only two!

The first rule is carbon at the corners. What does this mean? Well, at every corner where you do not see a letter (an atom), there is an implied carbon. This shorthand notation allows us to show the structure without writing in each single carbon. There is also an implied carbon at the end of every line. Using this rule, let's place carbons at the corners and the ends of the lines.

Now that we have the carbons in place, let's move to the next rule: hydrogens bonded to carbons are implied. To understand this rule, we must first understand the bonding properties of carbon. Carbon likes to make four bonds with other elements in order to satisfy the octet rule. Some of these carbons do not appear to have four bonds. For example, let's take a look at the leftmost carbon in the upper left corner. It has only bonded once (with nitrogen), so it has three bonds left. According to our rule, these three bonds are with hydrogen atoms. So, we can draw the three bonded hydrogen atoms for our carbon atom. It will look like this:

The carbon atom is now "happy" since it has bonded with four other atoms. Let's apply this hydrogen bonding rule to the rest of the carbons. Now, our structure will look like this:

We can now determine the chemical formula for caffeine. By looking at the structure, we can determine that we have carbon (C), hydrogen (H), oxygen (O), and nitrogen (N). By counting up the number of atoms for each element, we can determine that there are 8 carbons, 10 hydrogens, 2 oxygen, and 4 nitrogens.

We can write the chemical formula of caffeine: C8H10N4O2.

Now you can determine the formula for any chemical just by looking at its structure!
________
Image Credit:
(1) “Caffeine Chemical Structure.” Wikimedia Commons, upload.wikimedia.org/wikipedia/commons/thumb/5/5e/Caffeine-2D-skeletal.svg/934px-Caffeine-2D-skeletal.svg.png.

Comments

The Plasma Membrane and the Fluid Mosaic Model

Let's take a look at a cell. One thing that you will find common among all cells is the cell membrane - whether it's an animal cell, a plant cell or a bacterial cell. While this layer may only be ten nanometers thick, it has an intricate molecular structure designed for efficient transport of material into and out of the cell. This property is known as selective permeability , the control of the passage of materials across the cell membrane. The cell membrane is designed in a way that substances having certain properties are unable to enter or leave the cell (this movement across the cell boundary is known as transport ). The fluid mosaic model describes how substances, mainly cholesterol, phospholipids and proteins, slide freely in the membrane. First, let's start with the phospholipid bilayer . A phospholipid a complex lipid with a "head" and a "tail". The head is made of one polar/hydrophilic phosphate group and a glycerol molecule. The ta

Paul Broca and "Tan"

Paul Broca is one of the most influential neuroscientists best known for his patient, Tan. Well, his name wasn't really Tan. His name was Louis Victor Leborgne, and his incredibly unusual neurological disorder settled a debate about the location of language capabilities in the brain. In 1861, Leborgne approached Broca at the Bicetre Hospital to receive surgery for a leg infection. Leborgne had suffered from several medical conditions prior to his surgery; he had epilepsy at a young age and subsequently lost his ability to produce fluent speech. It was Leborgne's language disorder that really caught Broca's attention. Leborgne could think properly, but whenever he tried to communicate with Broca and verbalize his thoughts, all that came out of his mouth was the meaningless word "tan." For this reason, many scholars of neuroscience simply refer to Leborgne as "Tan". Broca realized that he could learn about our language capabilities by studying Leborg

Myelination

Neurons can transmit signals at astonishing speeds - some signals can travel as fast at 268 miles per hour! How are neurons capable of such speeds? Well, their axons, which transmit signals to other neurons, have a special covering known as the myelin sheath. Myelin, a lipid-rich substance, insulates the axon and increases the speed of signal transmission. As an action potential travels down the axon, some ions may cross the membrane and exit the cell. However, the presence of myelin prevents this escape. In the peripheral nervous system, myelin is found in the membranes of Schwann cells, a type of glial cell. Each Schwann cell forms one unit of myelin. In the central nervous system, oligodendrocytes, another type of glial cell, tightly wrap around the axon to form several layers of insulation. Each process of an oligodendrocyte can form one segment of myelin for several different cells. Myelin is not the only special feature of neurons that accelerates signal speeds. There are

NeuroExplorer

Search This Blog