Monthly Archives: February 2016

What’s good to be a chemist

The work of a chemist is everyday a challenge, exciting when you find something new, sometimes stressful but rewarding. Having a chemistry degree in hand can open many doors such as:

Academic Institutions

You might work as a teacher at the university or in high school, teacher in primary or secondary school, or researcher in a university or industry.

Federal, State, and Local Government Agencies

  1. Drug Administration as a medicinal, analytical or biochemical chemist
  2. Department of Justice and other law enforcement agencies or analytical chemist
  3. Department of Agriculture as an agricultural, biochemical, Environmental, or analytical chemist
  4. Environmental Protection Agency, environmental, inorganic or organic chemist
  5. Patent Office as a patent researcher or lawyer
  6. National Science Foundation as a science writer and editor
  7. Department of Energy as an industrial and engineering, materials, or environmental chemist

Chemical Industries

Chemists produce everything from plastics and paints to pharmaceuticals products, flavors, fragrances, detergents, cosmetics, …

Business

Some chemists also work as business owners, consultants, art conservators, or even investment bankers.

Gravitational waves explained

A very good video about explanation of gravitational waves

https://www.youtube.com/watch?v=4GbWfNHtHRg

What are gravitational waves?

Colossal cosmic collisions and stellar explosions can rattle spacetime itself. Relativity rule predicts that ripples in the fabric of space-time radiate energy . After some time, they reach Earth, compress spacetime by as little as one ten-thousandth, the width of a proton.

How are they detected?

To spot a signal, LIGO uses a special mirror to split a beam of laser light and sends it down two 4-kilometer-long arms, at a 90 degree angle to each other. After ricocheting back and forth 400 times, turning each beam’s journey into a 1,600 kilometer round-trip, the light recombines near its source.

Capture d’écran 2016-02-20 à 10.56.33

 

flame test for the determination of metals or ions

Flame tests are used in chemistry to identify metals or ions in compounds. They are more useful for some metals than others; particularly for the Group 1 metals, they provide a good way of quickly identifying the metal ion present.

This picture looks at the colour of various metal and metalloid ions that occur during flame tests. Most people probably remember have seen one flame test (often sodium) during an experiment in  experimental lesson at school.Metal-Ion-Flame-Test-Colours-Jan-15-724x1024

To carry out the flame tests, a small amount of the compound being tested will be held in a flame and the colour given off observed. This colour originates from the movement of the electrons in metal ion. When heated, the electrons gain energy, and are « excited » into higher energy levels; however, the electrons occupying these levels is more energetically unstable, and they tend to fall back down to their original energy levels, releasing energy as they do so. This energy is released as light, with the characteristic flame colours of different metal ions due to varying electron transitions.

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Chemical actions of love on the brain !

“Love looks not with the eyes, but with the mind,” as Shakespeare’s Helena said and  neuroscientists would agree.

Love might seem to move in mysterious ways, but scientists actually have a pretty good idea of what love does to the brain. Being in love floods the brain with chemicals and hormones that produce feelings of pleasure, obsession and attachment.

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This funny little video shows you the chemical effects of love somebody on your body. And unfortunately the  chemical effects of a rupture …

In fact, your body is regulated such as a machine !! But this animation explains this with humor ..don’t be worry

https://www.facebook.com/IFeakingLoveScience/videos/1320720811282260/

 

Dynamic Periodic Table

On this Periodic Table  (link in end of my text), you have access on one click to the description of the elements, for example if you click on Co you have directly the cobalt wikipedia page which opens.

There are also the properties of each elements, just click on one, and you have access to the state of this element at 273 K, the melting point, boiling point, electronegativity, valence, …….

The bottom orbitals shows you the quantic cases with the spin. You have in the same way: n, m and l. And the representation of s, p,d and f orbitals corresponding to the element chosen.

Isotopes is an access to all isotopes for one element you have chosen.

And to finish Compounds permits you to have a list of compounds containing the element you have chosen.

http://www.ptable.com/?lang=en#Writeup/Wikipedia

Size exclusion chromatography

Size Exclusion Chromatography (SEC) consists on the separation technique based on the molecular size of the components, used for semi-preparative purifications and various analytical assays. It is a separation technique which takes the advantage of the difference in size of the molecules. separation is achieved by the differential exclusion from the pores of the packing material, of the sample molecules as they pass through a bed of porous particles. The principle feature of SEC is its gentle non-adsorptive interaction with the sample, enabling high retention of biomolecular activity.

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 Principe

Size exclusion chromatography (SEC) is the separation of a mixture based on the molecular size of the components in this mixture. The separation is achieved by the differential exclusion or inclusion of solutes as they pass through stationary phase consisting of pores of different sizes cross linked polymeric gels or beads. The process is based upon different permeation rates of each solute molecule into the interior of gel particles. Size exclusion chromatography involves gentle interaction with the sample, enabling high retention of biomolecular activity. The separation of organic polymers in non-aqueous systems is called gel permeation chromatography (GPC).

A column of  porous matrix is in equilibrium with a suitable mobile phase for the molecules to be separated. Large molecules are excluded from the pores will pass through the space  between the matrix and will come first in the effluent. Smaller molecules will get distributed in between the mobile phase of in and outside the molecular sieve and will then pass through the column at a slower rate,so appear later in effluent.

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Zika virus

Zika virus is an emerging mosquito-borne virus that was identified in Uganda in 1947 in Rhesus of monkeys. Subsequently, Zika virus was then identified in humans in 1952.

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Recently, in Brazil, local health authorities have observed an increase in Guillain-Barré, syndrome which coincided with Zika virus infection, in general, population with an increase in babies born with a microcephaly.

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A link has been established between Zika virus infection on pregnant women and microcephaly in babies born.

In fact, Zika virus is transmitted to people through the bite of an infected mosquito in tropical regions. Particularly known to circulate in Africa, the Americas, Asia and the Pacific.

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Virus diagnostics can only be confirmed by laboratory testing, Zika virus RNA can be found in blood or other fluids such as saliva,…

There are several signs and symptoms of Zika infection:

  • Fever
  • Conjunctivitis
  • muscle and joint pain
  • malaise
  • headache

These symptoms appear between five or seven days after incubation period of Zika virus.

Unfortunately, there is no specific treatment or vaccine currently available and the consequences are dramatic on brain of babies.

A Letter of Albert Einstein: the most important force is love!

“When I proposed the theory of relativity, very few understood me, and what I will reveal now to transmit to mankind will also collide with the misunderstanding and prejudice in the world.

I ask you to guard the letters as long as necessary, years, decades, until society is advanced enough to accept what I will explain below.

There is an extremely powerful force that, so far, science has not found a formal explanation to. It is a force that includes and governs all others, and is even behind any phenomenon operating in the universe and has not yet been identified by us. This universal force is LOVE.

When scientists looked for a unified theory of the universe they forgot the most powerful unseen force. Love is Light, that enlightens those who give and receive it. Love is gravity, because it makes some people feel attracted to others. Love is power, because it multiplies the best we have, and allows humanity not to be extinguished in their blind selfishness. Love unfolds and reveals. For love we live and die. Love is God and God is Love.

This force explains everything and gives meaning to life. This is the variable that we have ignored for too long, maybe because we are afraid of love because it is the only energy in the universe that man has not learned to drive at will.

To give visibility to love, I made a simple substitution in my most famous equation. If instead of E = mc2, we accept that the energy to heal the world can be obtained through love multiplied by the speed of light squared, we arrive at the conclusion that love is the most powerful force there is, because it has no limits.

After the failure of humanity in the use and control of the other forces of the universe that have turned against us, it is urgent that we nourish ourselves with another kind of energy…

If we want our species to survive, if we are to find meaning in life, if we want to save the world and every sentient being that inhabits it, love is the one and only answer.

Perhaps we are not yet ready to make a bomb of love, a device powerful enough to entirely destroy the hate, selfishness and greed that devastate the planet.

However, each individual carries within them a small but powerful generator of love whose energy is waiting to be released.

When we learn to give and receive this universal energy, dear Lieserl, we will have affirmed that love conquers all, is able to transcend everything and anything, because love is the quintessence of life.”

Distillation under reduced pressure

When use a reduced pressure distillation?

If heated when the product produce its decomposition it must be distilled under reduced pressure. The decomposition may occur with explosive violence and this can occur even at room temperature if impurities are present.

To overcome this difficulty, the liquid is distilled under reduced pressure, so that its boiling-point shall be definitely below its thermal decomposition point.

Assembly

distillation ss p° red

 

The video explains when it is useful to use a reduced pressure for make the distillation, the procedure but also all the pieces of a vacuum distillation

https://www.youtube.com/watch?v=i3b3SxN9wI8

 

 

Chemistry Quiz

You want to improve your knowledges or just make an evaluation of you level, on this website you will find several quizzes about all the main fields in chemistry.

Also very useful for make a little review before an exam, you have the choice of the theme …

You can also have the choice for the level: easy ——> difficult

http://www.rsc.org/learn-chemistry/wiki/Quiz:Overview

Take fun .