Category: Chemistry

Why do phone batteries last a short time?

Why do phone batteries last a short time?

Why do phone batteries last a short time?

10/21/16

“Well, why do they?”
Batteries are one of the most indispensable drivers of modern civilization. And smartphones are of the chief applications of this technology. However, how is it that something so pivotal to society’s function wear out it’s sole power source so rapidly? Well, let’s think about it like an Engineer would. We know that batteries are powered by releasing stored chemical energy through reactions. However, batteries have a low energy density, meaning that a large battery will hold a relatively small amount of energy compared to it’s size. And since phones need to be smaller for practical use, the battery has to be small as well, and since the only other way to increase battery capacity is to increase the efficiency (which would increase costs prohibitively), smartphone users are stuck with low battery lifetimes!

Chemical hybridization

Chemical hybridization

Chemical hybridization

10/20/16

“How can covalent bonds occur if the elements are in different orbitals?”
There seems to be a problem when it comes to covalent bonding. Bonding theory states that bonds occur because of an overlap of of atomic orbitals.Much of the time, the central element will have  different orbitals than the surrounding ones. So how can chemical bonding occur? Well, nature can be very clever. What happens is that the subshells will hybridize to become one big subshell. Each electron will try to fit into it’s own shell in the subshell. If there is overlap, then there will be a lone pair of electrons.To illustrate, an element with orbitals of s2 p2 will become sp3, as the second electron from s2 will have extra room. With hybridization, chemical bonding can occur.

Lewis structures

Lewis structures

Lewis structures

10/19/16

“How can we geometrically represent chemical bonds?”
Chemical bonds are one of the most fundamental aspects of Chemistry. But when a student of science is first introduced to them, they are simply shown them in a purely conceptual form. But how can we make a more accurate representation of what these structures actually look like? Well, let’s think about it. We know that some elements can covalently bond with one another by sharing orbital electrons. So what if we just drew structures that represented these orbital bonds? This is the fundamental principle behind a tool that called Lewis structures. There are several steps to forming a Lewis structure. The first is to identify the element in the bond with the least amount of electronegativity (With the exception of hydrogen). Then one has to place the rest of the elements around the aforementioned low-electronegativity element. Then, one must place the associated valence electrons around each of the element. Since all non-noble gas elements will have some of their electron orbitals free, there will be a need for some of the valence elements to form covalent pairs with others to obtain the necessary filled valence shell. Afterwards, if there are still more electrons that need to be filled, then double and triple bonds can be formed to increase the amount of valence electrons. If all valence electrons on the outer elements are filled up and the inner element still needs or has more valence electrons, then the surplus electrons will form lone pairs on the central element.

Phenolphthalein

Phenolphthalein

Phenolphthalein

10/17/16

 

“How do we can we find out if an acidic or basic reaction is occurring?”

 

When doing Chemistry, we will have to perform a lot of chemical reactions. However, sometimes these reactions can be invisible to our eye. Therefore, finding a way to know if a chemical reaction is going on would be quite a necessity to our interests. Since there are many types of chemical reactions, let’s start with one kind, acid-base reactions. So how can we know if acid-base reactions are going on? Well, let’s think about it for a moment. We know that when a base reacts with an acidic solution, hydronium ions[HO3] are released. And we know that weak acids not only can react with these hydronium ions but are also dissolved but not dissociated in solutions. This means that hydronium atoms can exist within a solution without altering the chemical properties much. Now all we have to figure what type of weak acid would be pertinent to our interest. Well, luckily for us, Chemists have discovered an element known as Phenolphthalein which actually changes it’s color depending on the pH of the surrounding substance! Specifically, Phenolphthalein will become clear in the case of a net acidic reaction, and pink in the case of a basic reaction. Phenolphthalein is used for chemichal purposes all over, whether it is for tritration or simple reactions.

Abbreviated electron configuration

Abbreviated electron configuration

Abbreviated electron configuration

10/15/16

“What is a simpler way to present electron configuration?”

 

Electron configuration is one of the most fundamental aspects of chemistry. However, it is also one of the most tedious. Why would you want to write series and series of numbers and letters just to represent one element? Well, how about we look at some patterns in the periodic table to help us out. We know that orbitals are only completed when all of the subshells in that level have been filled, and this phenomena only occurs in non-ionized noble gases. An when we advance past a particular noble gas on the periodic table, the whole naming process will start over again (for example, after helium [He] the second orbital will start,and after neon [Ne] the third will start). Since we would know all of the subshells filled up to that point, how about we just list the subshells that come after the last noble gas? For example, titanium [Ti] will become [Ar] 4s2 3d2. This notation is much easier to read and understand than the old drawn out notation.

 

Well, luckily for us, chemists tend to be a fairly intelligent people, so they have instrumented a system known as abbreviated electron configuration to help us. Abbreviated electron configuration

Spin quantum number

Spin quantum number

Spin quantum number

10/05/16

“How can we describe the angular momentum of an electron?”

 

The orbits of electrons around the central nucleus of an atom is a very complex matter. And because of this, we will have think to think of creative ways to describe the myriad of elements that make it up. So to make things simpler break this problem down into smaller components, such as the angular momentum. When an electron transits around the central nucleus, it has both an angular momentum from the orbit and another one resulting from the spin around it’s own axis. The combination of these two elements will result in a vector quantity called the spin quantum number. The spin quantum number represents the magnitude (½) and the direction 9+ or -) hat the angular momentum of the current electron. When electrons enter into subshells, they enter each orbital that is currently unoccupied. If the elements only has unpaired electrons, then this spin quantum number will be considered positive, and if the electrons begin to pair up, then the spin quantum number will be considered negative.

Hydrophobic substances

Hydrophobic substances

Hydrophobic substances

10/03/16

“Are there substances that are repelled by water?”
You are probably familiar with water. I mean, it’s the basic principle of all life on this planet! And this importance derives from the fact that water can form bonds with nearly all sets of compounds. However, are there substances that are not only insoluble by water but actively repel it? Well, let’s think about how such a substance could exist. The first thing we should analyze is what makes water so bondable, and that comes as a consequence of the polar nature it’s structure. So logically speaking, shouldn’t nonpolar elements have difficulty bonding with water? This is the operating principle behind hydrophobic substances. Examples of hyrophobic molecules include alkanes, oils, and fats.

Boron carbide

Boron carbide

Boron carbide

10/02/16

“Why is bullet proof armor bullet proof?”
We are all probably familiar with bullet proof vests. These amazing pieces of technology have saved countless of lives through their simple yet intuitive design. However, what makes these vests so durable? Well, the answer lies in it’s composition, specifically, the fact that it’s made out of a very special compound called Boron carbide. A single molecule of Boron carbide is derived from four boron atoms and one carbon atom. But this is not just what makes boron carbide special. What makes this molecule special is it’s extreme durability. Namely, the fact that it is the third hardest substance known to humanity behind diamond and cubic boron nitrade. And out of these three substances, it is the only one that can be easily mass-produced! Because of this, Boron carbide is the number one choice for application in military necessities such as ballistic armor, tank covering, and even nuclear plating! Boron carbide also has non-military applications found in high pressure jet cutter nozzles, padlocks, and for control rods in nuclear power generation.

Lipids

Lipids

Lipids

Isaac Gendler

“What is your fat made out of?”
Everyone has fat on their bodies, but have you ever wondered what it is made out of? Well, it turns out that body fat is composed of an interesting class of molecules called lipids. Lipids are molecules that contain hydrocarbons and are insoluble in water due to their non-polar structure. This composition also makes them hydrophobic. These liquids form an essential part of a creature’s biology. In fact, we can obtain a reasonable amount of lipids by consuming the fat of other animals.