Category: Chemistry

The Strange Second State of Water

The Strange Second State of Water

 

The Strange Second State of Water

09/17/17

“Can water have a second liquid state?”

 

Water is a most peculiar molecular compound. Although this material composes over sixty percent of the human body and the vast majority of the Earth’s surface area, we still know very little about the chemical and physical properties and behaviors of this element. And this idea could not be better exemplified by a most recent discovery lead by a highly intelligent group of scientists.

At Oxford University, A group of physicists led by the postdoctoral research assistant Laura Martinez Maestro had decided to conduct a new experiment on water (Crew, Bec). For this, they took a sample of water at zero degrees Celsius and increased the temperature slowly until it reached one hundred degrees Celsius while measuring the thermal conductivity, refractive index, conductivity, surface tension, and the dielectric constant. Once the water hit, 40 degrees Celsius, its properties started to shift drastically, and once it had hit 60 degrees Celsius all of its properties had changed into something new. Specifically, the temperature of change was 64 degrees Celsius for thermal conductivity, 50 degrees Celsius for refractive index, about 53 degrees Celsius for conductivity, and 57 degrees Celsius for surface tension.

Why does this happen? Although everything seems murky at the moment, this phenomenon might be a consequence of the fact that water molecules only have a very weak bond with one another, and that the bond between oxygen and hydrogen is far greater than the hydrogen-hydrogen bonding. As a result, the molecular structure of  molecules is constantly changing and reforming, leading many to believe that this might be the cause for the strange second stage of matter

 

References

Crew, Bec. “Physicists Just Discovered a Second State of Liquid Water.” ScienceAlert, ScienceAlert, 14 Nov. 2016, http://www.sciencealert.com/physicists-just-discovered-a-second-state-of-liquid-water.

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On water’s expansion with freezing

On water’s expansion with freezing

On water’s expansion with freezing

09/16/17

“Why does water expand upon freezing?”

The variation of volume with thermal energy for most liquids has a very simple characteristic. When heat is applied, the volume increases, and vice versa for cooling. This is because the added (or subtracted) energy will cause the amplitude of the vibrations of the molecules to change, thereby modifying the volume. For example, when a liquid freezes, the molecules will pack into one another, thereby shrinking the volume.

However, water exhibits a very peculiar phenomenon. When water is cooled to its freezing point, its volume will actually expand. Why does this happen? Well, let’s analyze it using our scientific mindset. Unlike most other molecules, water has a very unusual structure. Specifically, a water molecule’s primary form of bonding is based on hydrogen bonding. When temperature decreases, the strength of a hydrogen bond actually increases (since the lower thermal energy means that the hydrogen bonds will have less vibrational energy, therefore lowering the chance to shake out of position and increasing stability).

Once water is cooled into ice, the only bonding will be hydrogen bonding. Specifically, it will be bonded in a hexagonal structure, which is a much more “open” network than most structures. The tandem of hydrogen bonding and a hexagonal structure vastly decreasing the density (Levine, Scott 2013). And because density is described by the equation, with being the density,  being the mass, and being the volume, and as mass is constant, when the density decreases the volume must increase as a result. Consequentially, the volume of water increases upon freezing! This fact has multiple implications. For example, a lower density of ice means that ice will float in water, which allows for complex structures such as ice glaciers to occur naturally.

 

References

“Why Does Water Expand When It Freezes? .” FAQ: Water Expansion on Freezing, New York University, 3 Dec. 2013, http://www.iapws.org/faq1/freeze.html.

Solar paint

Solar paint

Solar paint

07/01/17

“Can we use paint to make energy?”

 

Paint is usually seen as just a covering used to keep mold away or for making art. However, is it possible to do more with this material? Well, let’s analyze this using our scientific mindset. If we were to mix in titanium oxide into paint, then it would be capable of absorbing sunlight to convert the moisture into hydrogen and oxygen, therefore allowing for the consumption of hydrogen energy. This tecnology is currently being developed by a team at RMIT in Australia and could revolutionize sustainable energy generation, allowing for easy residential level consumption! 

Cosmic dust

Cosmic dust

Cosmic dust

05/25/17

“What is that outer space dust made out of?”

 

Out in space there seems to be a very peculiar material, something akin to a cosmic dust. However, exactly is it and what is it made out of? Well, let’s start from a scientific perspective. If one were to put some of this cosmic dust under a microscope, then we would see that not only it is only a few molecules in size, contains organic matter, and is physically porous in nature. This interstellar dust is found between planets, and given its size is so small that infrared telescopes are often needed to study it.

Ethanol fuel

Ethanol fuel

Ethanol fuel

06/27/17

“Can we use plants to make fuel?”

 

Plants can be found everywhere on this planet, from the sandiest deserts to the densest rainforests. And like animals, all of these plants have one thing in common, stored energy! So logically speaking, couldn’t we convert some of this plant matter into a fuel for our own use? Well, let’s use our scientific mindset to find out.
First, let’s gather up some plants with starches and sugars such as corn grain and place it in a production facility. Then, let’s break it down into its component sugars and convert into a chemical called ethanol. Ethanol is a flammable liquid that can be used to power internal combustion engines. Because of its wide availability in agricultural areas, ethanol fuel is a popular choice in the nation of Brazil and the Great Plains of the United States.

Chemical activity series

Chemical activity series

Chemical activity series

06/13/17

“How can we predict if an atom will react with another atom or not?”

 

If you ever decide to take a chemistry class, you will probably have to solve a lot of chemical reactions sets. However, have you ever wondered whether or not if these sets can be achieved or not? Well, in the natural world, it has been empirically investigated that some elements are more reactive with others. And in fact, this has found to be a linear correlation. To illustrate, let’s say that elements x is more reactive than element y which is more reactive than element z, then element x will also be more reactive with element z. If you put together an entire list of all of the reactivities of the periodic table of elements, you would build something that is called a reactivity series. The most reactive element is fluorine [F], and the least reactive metal is neon[Ne]

Valence gap

Valence gap

Valence gap

06/05/17

“Why are materials electrically insulative, conductive, or semiconductive?”

 

All materials fall into one of three classifications when it comes to moving an electric current, insulative, conductive, or semiconductive. However, what property determines this? Well, let’s look at the atomic level to find out. When multiples atoms come close together, their possible energy states branch out into multiple bands. The two most important bands are the valence (which holds the outermost electrons) and conduction bands (which holds electrons ready to conduct) These bands will be separated by a valence gap.. If there is no difference, then it takes no extra energy to conduct energy and the material is conductive. If there is a noticeable but surmountable gap then the material is semiconductive. And if it is impossible to reach then it is insulative. You can think of it like the distance to a basketball hoop, the higher the height the more energy is required.