Category: Chemistry

The environmental impact of methane

The environmental impact of methane

The environmental impact of methane

12/18/16

“What damage to humanity does the emission of methane cause?”

 

Most of the discourse surrounding pollutive emissions centers on carbon dioxide. However, there are other greenhouse gasses that have an equivalently repugnant impact on the environment such as methane. Methane, with the molecular formula of CH4, is released from the operation and transport of coal and natural gas. Scientific studies have shown that methane is over 25 times more potent in trapping heat than carbon dioxide! In fact, methane is so dangerous that the American EPA has recently created a new ruling to regulate the emission of this gas (which are estimated to not only save the equivalent of 11 metric tons of Carbon dioxide but also yield economic benefits of 690 million USD).

Electrolytes

Electrolytes

Electrolytes

12/16/16

“What are those electrolytes that I often hear about?”

 

During sports drinks commercials, you probably hear the term electrolytes tossed around a lot. However, what exactly are these electrolytes? Well, electrolytes are simply substances that produce an electrically conducting solution when dissolved in water. For example, Sodium [Na+] and Potassium[K+] are positive electrolytes. Electrolytes are extremely important to the functioning of a healthy human body since the cells that compose it use the material of electrolytes to maintain a voltage potential across their membrane and to carry electrical impulses (such as nerve connections and muscle contractions) alongside your body. Replacing electrolytes are especially important if you contract a stomach flu, as such support will become depleted with the advent of such a situation.

Burettes

Burettes

Burettes

10/09/16

“How can we  save headaches with precise pouring in chemistry labs?”

 

Doing labwork in chemistry can be very taxing on one’s patience. For example, we might have to pour a solution up with a high decimal value of precision, and even a slight spill can lead to disaster in an experiment! But how can we simplify this? Well, let’s use our engineering mindset to solve this scientific problem. What if we were to create a hyper-accurate glass tube that had a cork on the bottom, which when pulled, would release all of the solution? Wouldn’t this allow for a complete transfer of the liquid that we are working with?  This is the operating principle behind a Burette. Burettes are used widely in chemistry labs for their dual accuracy in measurement and safety.

Organic chemistry functional groups

Organic chemistry functional groups

Organic chemistry functional groups

12/11/16

“What causes Organic molecules to have special properties?”

 

Organic compounds are some of the most peculiar forms of nature, making up much of the natural world that we observe. But what makes organic chemicals even more important is that they can be divided into components called functional groups. Functional groups are portions of organic molecules that can be classified into different parts. For example, the thiol chain can be thought of as one such functional group. The composition of functional groups within an organic molecule can change the properties of said molecule, such as the boiling point or smell. There are over 20 functional groups currently identified by Chemists (and for all we know there could be more to come!)

Thiol

Thiol

Thiol

12/10/16

“Why do skunk odors smell so bad?”

 

Have you ever had the misfortune to smell skunk odor? It’s a really bad experience, one that I can thankfully say that I never had. But with a little bit of science, we can all understand why skunk can produce such bad smells.  When a skunk releases its odors, the resulting gas will contain an organic chemical with a most peculiar part known as thiol. Thiol is an organic functional group with an -SH for one of its branches. The sulfur component of thiol is what causes its bad smell. But thiols are not limited exclusively to skunk scents,but can be found in recently chopped onions and even jet fuel!

Hess’s law

Hess’s law

Hess’s law

12/05/16

“How can we find the change in enthalpy for a chemical reaction without actually performing the reaction?”

Finding the change in enthalpy for a chemical reaction is a rather straightforward procedure, one simply carries forward with the necessary steps and measures the temperature before and after the reaction took place. However, some reactions take an extraordinary long time to perform, or their process is highly volatile. So how can we find the change in enthalpy for such reactions? Well let’s think about it. We know that if we were to take one chemical reaction and reverse it, then the resulting change in enthalpy would reverse in sign. And we know that if we add one element of a chemical equation to the opposite side of an equation containing that element, then they would cancel out. So what if were to take the results of some reactions that we already know, modify them if necessary, and then add them together to fashion the equation of the reaction that we desire? This is the operating principle behind Hess’ law.

To illustrate, let’s examine the reaction Mg(s) + H2O(l) → MgO(s) +H2(g). Since Mg does not react with water, completing this experimentally would be a nightmarish process. However, we can easily obtain the results for Mg(s) +2HCL(aq) → MgCl2(aq) + H2 and MgO(s) + 2HCl(aq) → MgCl2(aq) + H2O. If we were to take the former equation and subtract the latter from it, we would be able to obtain our desired equation. All we need to do is obtain the change in enthalpies for these reactions, and then proceed forward with the mathematics, and next thing you know we would obtain our necessary results!

Change in Enthalpy

Change in Enthalpy

Change in Enthalpy

12/04/16

“How can we measure the change of energy in a thermodynamic system when the system itself changes?”

 

All thermodynamic systems have the summation of the parts of their energy represented by enthalpy. However, the universe is almost never in a static state, and is always changing. Consequently, all thermodynamic systems will be in perpetual change as well. And it turns out that this change in enthalpy has very practical results for scientific use. A change in enthalpy can be quantitatively described by taking the difference of the enthalpy of the system after the change and before the change. If the  enthalpy has gone up, then that means that energy must have been added to the system, making it an endothermic process. If the enthalpy has gone down, then heat was removed from the system and it was an exothermic process. The change in Enthalpy is often symbolically represented using a (delta)H

Enthalpy

Enthalpy

Enthalpy

12/03/16

“How can we model the total energy inside a thermodynamic system?”

 

As a scientist or engineer, if you ever work with thermodynamics systems, then you will have to understand the amount of energythat you are working with. However, how can we represent this concept in more concrete terms? Well, luckily for us, after many years of hard labor, scientists and engineers have formulated the very concept of enthalpy of this very matter. Enthalpy can be defined as the amount of energy stored within a thermodynamic system, which can be symbolically defined as H = u + p*V, with H being the enthalpy, u being the internal energy of the system, p being the pressure and V being the volume.

Energy density and it’s importance

Energy density and it’s importance

Energy density and it’s importance

12/02/16

“How do scientists and engineers measure the density of energy within a system and why is it important?”

Energy is a quantity that is used omnipresently for calculations in all branches of science and engineering. However, energy is more than a theoretical abstraction, and since it is tied to the material universe, it must be stored somewhere in reality, such as in objects. And since objects of the same size can have different abilities to hold energy , we will need some conceptual way to understand this. As a result, scientists and engineers have developed the concept of energy density to represent the amount of energy stored within in object. Energy density is an important concept because when analyzing energy storage mechanisms such as batteries and capacitors, once must take in to consideration the volume vs power limitations that a project might have. To illustrate, let’s say that you want to build an autonomous boat. Since this boat will have no people on board, it will need a mechanism to power it’s systems. However, the boat can not uphold too much weight, or else it will sync. Therefore, when designing such a contraption, engineers will have to choose an energy storage technology with a high energy density.