Category: Chemistry

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.

Bomb calorimeters

Bomb calorimeters

Bomb calorimeters

06/02/17

“How can we measure the calories present in food?”

 

In our modern health obsessed world, we would like to know the calories contained in all foods. However, how can this even be determined in the first place? Well, let’s think back to a bit of prior knowledge. We know that calories are another way of saying energy and that we can measure the energy content of fuels using calorimeters. So what if we were to make a special type of calorimeter to find the energy contained in foods? Well, let’s put our engineering mind to the test.

 

First, let’s get a big tub of water. Then, let’s take a sample of our food, place it in an insulating case with some oxygen, attach it to an ignition coil, and place everything in the water. When we activate the ignition unit, the ignition coil will cause our sample to explode and raise the temperature of the water. From the measured temperature change, we will be able to measure the calories contained in the sample! This device is known as a bomb calorimeter and is used in food labs all over the world.

Calorimeters

Calorimeters

Calorimeters

06/01/17

“How can we determine the energy composition of a fuel?”

 

Fuels are one of the most vital pieces of operation for modern transportation. However, how do scientists determine the amount of energy contained in them in the first place? Well, let’s think about it. We know that if we ignite fuel, then we can get a fire. And we also know that this fire can heat objects such a cup of water. And we also know that if we measure the change in temperature of this water, then we can obtain the amount of heat added. So what if we were to combine all of the processes to make an energy measuring device? Well, this is the fundamental idea behind a calorimeter and is used in industrial operations all over this planet.

Refractory materials

Refractory materials

Refractory materials

05/31/17

“Are there materials that retain their strength at exceedingly high temperatures?”

 

For processes such as nuclear power generation or incinerators, materials must be able to withstand heavy loads. However, the high temperatures that they operate at often destroy the useful properties of most materials. So are there materials that can withstand high temperatures? Well, after many years of hard work spent in research, Materials Engineers and Scientists have been able to classify such materials as refractory materials. Refractory materials can be divided into two types, acidic refractories with SiO2 content more than 93% used for their erosion resistance, and basic refractories for higher thermal resistance

Fractional distillation

Fractional distillation

Fractional distillation

05/28/17

“How can we have distillation for materials with more than two substances?”

 

Distillation is the process of separating two substances using the science of evaporation and condensation in regard to different boiling points. However, how can we make this process happen for materials such as crude oil which are composed of many different substances? Well, let’s use our engineering mindset to find out. Let’s start out with a simple test tube. In this test tube, let’s also have another smaller tube at the midsection leading to a stationary beaker. Now let have the bottom portion of the main tube be immersed in a hot fluid. When we dispose a material into the tube, the hot fluid will heat the material until one of the substances evaporates. The gas from the evaporated substance will rise and move through the tube, eventually reaching the midsection tube, cooling and condensing into a liquid form in the beaker. Once all of this substance has been removed, we can swap out the old stationary beaker for a new one, replace the hot liquid with a bunsen burner, and repeat the process. This procedure is known as fractional distillation and is commonly employed for separating substances with numerous hydrocarbons.

Cross-linking

Cross-linking

Cross-linking

05/20/17

“What happens when polymer chains link together?”
Polymers are famous for their absolutely long chains. However what happens when these chains link together? Well, let’s use our scientific mindsets to find out. If we look carefully, then we will observe that the density of the materials will go down (since now all of its composing elements will no longer be able to be squeezed together so easily) but the strength will increase since the there are now three-dimensional impediments to dislocations.