What Does a Chemical Scientist Do?

A chemist generally refers to a scientist who is engaged in modern and modern chemical research. He has full-time and part-time jobs. In the United Kingdom, he can also refer to a pharmacist. Chemistry is a natural science that studies the composition, structure, properties, and changes of matter at the atomic level, while chemists are workers who specialize in the study of these substances and their properties. Chemists study chemical elements, atoms, molecules, and how they interact. Chemists also research and test drugs, explosives and the like. Chemistry is a very important science, because most new drugs are now developed through chemical technology.

chemist

(Group of people studying chemistry)

What makes a chemist different from others is that they usually check carefully for changes in every object around them. Most of their work is to study how to mass produce a variety of expensive medicinal or industrial chemicals in order to benefit the public or make a living.

Every chemist will have a different

Mendeleev

Mendeleev: (Russian: , February 8, 1834-February 2, 1907) Russian chemist. Born in Tobolsk, Siberia on February 7, 1834, and died in St. Petersburg on February 2, 1907. In 1850, he entered St. Petersburg Teachers College to study chemistry. After graduating in 1855, he became a teacher of Odessa Middle School. In 1857 he was an associate professor at St. Petersburg University. In 1859 he went to the University of Heidelberg for further studies. In 1860 he participated in the International Congress of Chemists in Karlsruhe. In 1861 he returned to St. Petersburg to work on scientific writing. In 1863, he was a professor at the Institute of Technology, and in 1865 he received a doctorate degree in chemistry. Saint Peter in 1866

Mendeleev

Professor of General Chemistry at the University of Detroit. In 1867, he served as the director of the Department of Chemistry. Since 1893, he has been the director of the Bureau of Weights and Measures. Elected a foreign member of the Royal Society in 1890.

Biographies

Mendeleev ( ) was born on February 7, 1834 in Tobolsk, Siberia, and died in Petersburg on February 2, 1907.

He entered the Petersburg Technical College in 1848, and entered the Petersburg Teachers College in 1850 to study chemistry.

He obtained a higher degree in chemistry in 1856, and for the first time obtained a university position in 1857. He was an associate professor at the University of Petersburg. In 1859 he went to the University of Heidelberg for further studies.

In 1860 he participated in the International Congress of Chemists in Karlsruhe.

In 1861 he returned to Petersburg for scientific writing. In 1863, he was a professor at the Institute of Technology. In 1864, Mendeleev was a professor of chemistry at the Technical College. He received a doctorate in chemistry in 1865.

In 1866, he was professor of general chemistry at Petersburg University, and in 1867 he was the director of the chemistry department.

Since 1893, he has been the director of the Bureau of Weights and Measures. Elected a foreign member of the Royal Society in 1890.

On February 2, 1907, the famous Russian chemist Mendeleev died at the age of 73. [2] To commemorate this great scientist, in 1955, A.Gniorso, BGHarvey, GRChoppin and others in the United States bombarded plutonium (253Es) with helium in an accelerator, Tritium was combined with a helium nucleus to emit a neutron, and a new element was obtained. It was named Mendelevium (Mendelevium, Md) after Mendeleyev.

Major achievements

Mendeleev's greatest contribution was the discovery of the periodic law of chemical elements. Today called Mendeleev's law of the cycle. In February 1869, Mendeleev compiled a periodic table containing all 63 elements known at the time (Table 1). In March of the same year, he commissioned NA Menshutkin to read a paper entitled "Relationship between the Attributes of Atomic Elements and Atomic Weight" at the Russian Chemical Society, explaining the main points of the periodic law of elements:

The elements arranged according to the size of the atomic weight show obvious periodicity in nature.

The size of the atomic weight determines the characteristics of the element.

The discovery of many unknown elements should be expected. For example, it is expected that there should be elements similar to aluminum and silicon with atomic weights between 65 and 75.

When the same element of some element is known, the atomic weight of the element can sometimes be corrected.

In 1871, Mendeleev published the paper "Periodic Dependence of Chemical Elements", which further explained the periodic law of chemical elements. He also revised the periodic table of chemical elements (Table 2), and changed the vertical table in 1869 to a horizontal column, highlighting the regularity of the element family and period; divided the main and sub-groups, making them basically modern Form of the periodic table.

In the process of discovering the periodic law and making the periodic table, Mendeleev changed the positions of certain elements (Os, Ir, Pt, Au; Te, I; Ni, Co), regardless of the then recognized atomic weight, And considering the reasonable position in the periodic table, the atomic weights of some other elements (In, La, Y, Er, Ce, Th, U) were revised, and the existence of some elements was predicted. In the Periodic Table of the Elements in 1869, Mendeleev left open spaces for four undiscovered elements. In 1871, he published a paper "The Natural System of Elements and Using It to Specify the Properties of Certain Elements", and made detailed predictions about the existence and properties of some elements, such as aluminum, boron, and silicon, and their atomic weight. There are six such vacancies. Mendeleev's inferences were confirmed by subsequent chemical experiments.

The discovery of the periodic law of the elements has stimulated the enthusiasm for discovering new elements and studying the theory of inorganic chemistry. The discovery of the periodic law of the elements is an important milestone in the history of chemical development. It systematically accumulated a large amount of knowledge about various elements over hundreds of years, forming a unified system with internal connections, and then making it a theory.

Mendeleev also studied the relationship between gas and liquid volumes and temperature and pressure. In 1860, he discovered the critical temperature of gas and proposed an empirical formula for the thermal expansion of liquids. In 1865, the nature of the solution was studied, and the hydrate theory of the solution was proposed, which laid the foundation for the modern solution theory. From 1872 to 1882, he and his students accurately measured the compression coefficients of several gases.

Mendeleev was awarded the David Medal by the Royal Society for discovering the law of cycles. He also received the British Copley Medal. In 1955, in honor of Mendeleev, the discoverer of the periodic law of the elements, the 101 element was named . Mendeleev wrote the book "Principle of Chemistry" using the cyclical view of the nature of elements, which has been translated into English, French and other languages.

Lady in chemical house

Marie Curie (1867-1934), a Polish scientist of French nationality, studied the radioactive phenomenon and found two kinds of radioactive elements, radium and thorium, and won the Nobel Prize twice in her life. As a distinguished scientist, Mrs. Curie has the Institute of General Scientists

Madame Curie

No social impact. Especially because of being a pioneer of successful women, her example inspired many people. Many people heard her story as a child but got a simplified and incomplete impression. What the world knows about Mrs. Curie. Much influenced by the second woman's biography MadameCurie, published in 1937. This book beautified Madame Curie's life and dealt with the twists and turns that she encountered in her life. American biographer Susan Quinn spent seven years collecting undisclosed diaries and biographical material, including Curie family members and friends. A new book, Maria Curie: ALife, was published, which paints a more detailed and in-depth picture of her arduous, bitter and struggling life.

Life experience

If you just look at your resume, it's easy to think that Maria Curie is just a successful scientist. She was born in November 1867 in Warsaw, Poland. One brother and three sisters, both parents are teachers. When she was 15, she graduated from high school with the first place. He then worked as a tutor for several years. In 1891, he went to Sorbonne to receive a university education. He graduated in 1894 and obtained two certificates in mathematics and physics. In 1895, she married Pierre Curie, who taught at the School of Industrial Physics and Chemistry in Paris. In 1897, her eldest daughter Irène was born. Previously. She did magnetic research with Gabriel Lippman of Sorbonne and published her first thesis; at this time, in preparation for her doctoral dissertation, she started a new project in Pierre's laboratory, Pierre He soon joined his wife's work. Their experimental notes began on December 6, 1897, until February 17, 1898, when they recorded the first observation of a new radioactive element, polonium. After several months of follow-up and analysis, they made two important findings in a report formally submitted to the French Academy of Sciences for reading on July 18: one is the element plutonium, and the other is the concept of r radioactivity. The discovery of thorium purification and the separation of another new element, radium, has greatly stimulated chemical research; radioactivity research is a breakthrough discovery in the study of the nature of matter. In June 1903, Mrs. Curie defended her thesis and was awarded a doctorate degree in physical sciences. In early November, the Curie couple was awarded the Humphrey Davy Medal of the Royal Society; in mid-November, they learned that they won the Nobel Prize in Physics with Henri Becquerel in recognition of their research on radioactive phenomena. . In 1905 they had the second daughter, Eve. Pierre died in 1906. In 1911 Madame Curie won the Nobel Prize in Chemistry. In recognition of her discovery of radon and radium. Madame Curie died in 1934. In 1935 her eldest daughter, Ellen and son-in-law, Frédéric Joliot-Curie, won the Nobel Prize in Chemistry (their scientific discoveries were known to Mrs. Curie when she was alive). The Madame Curie, published by the second daughter in 1937, became a popular biography all over the world.

Major achievements

In the experimental research, Madame Curie designed a measuring instrument that can not only detect whether a certain substance has rays, but also measure the intensity of the rays. After repeated experiments, she found that the intensity of uranium rays is proportional to the uranium content in the material, and has nothing to do with the state of uranium and external conditions.

Madam Curie conducted a comprehensive inspection of known chemical elements and all compounds, and made important discoveries: An element called plutonium can also automatically emit invisible rays, which indicates that the element can emit rays. It is not just the characteristics of uranium, but the common characteristics of some elements. She refers to this phenomenon as radioactivity, and the elements with this property are called radioactive elements. The radiation they emit is called "radiation."

At the end of 1902, Madame Curie refined one tenth of a gram of extremely pure radium chloride and accurately measured its atomic weight. Since then, the existence of radium has been confirmed. Radium is a kind of extremely difficult to obtain natural radioactive material. Its shape is shiny, white crystals like fine salt, radium has a slightly blue fluorescence, and this is the beautiful light blue fluorescence. A woman's beautiful life and unyielding faith. In spectral analysis, it is not the same as the spectral line of any known element. Although radium is not the first radioactive element discovered by humans, it is the most radioactive element. With its powerful radioactivity, many new properties of radiation can be further identified. In order to make many elements further practical applications. Medical research has found that radium rays have very different effects on various cells and tissues. Those cells that reproduce quickly are destroyed by the irradiation of radium. This discovery makes radium a powerful tool for treating cancer. Cancer is composed of abnormally fast-growing cells, and the damage caused by radium rays is much greater than that of surrounding healthy tissues. This new treatment was soon developed in countries around the world. In the French Republic, radium therapy is called Curie therapy. The discovery of radium has fundamentally changed the basic principles of physics, and it is of great significance to promote the development of scientific theory and its application in practice.

Pasteur

Pasteur was born in 1822 in the town of Dors in eastern France. He studied at the university in Paris, majoring in natural sciences. His talent did not show up during his school days, and one of his professors rated his chemistry grade as "passing." But Pasteur was awarded in 1847

Pasteur

A doctorate degree soon proved that the professor's referee was too early. Pasteur, 26, jumped into the ranks of a famous chemist for his research on the mirror isomer of tartaric acid. in.

Major achievements

Pasteur is not the first person to put forward the bacterial doctrine of disease. Similar hypotheses have been previously proposed by Girolamo Ferrastro, Frederick Henry, and others. However, Pasteur has strongly supported the bacterial doctrine through a large number of experiments and demonstrations, and this support is the main factor that convinces the scientific community that the doctrine is correct.

If the disease is caused by bacteria, it seems logical to avoid immune disease by preventing harmful bacteria from entering the body. Therefore, Pasteur emphasized the importance of antibacterial methods for clinical medicine, and he had a significant influence on Joseph Lister who introduced antibacterial methods to the clinical surgery.

Harmful bacteria can enter the body through food and beverages. Pasteur has invented a method to destroy microorganisms in beverages (called Pasteurization), which virtually eliminates the source of contaminated milk infections where it is used.

Pasteur began researching anthrax more than half a year later, a serious infectious disease that affects cattle and many other animals, including humans. Pasteur has shown that a particular type of bacteria is the causative agent of the disease. But far more important than this is that he invented a weak strain of Bacillus anthracis. Injecting this weak strain into cattle will make the disease mild, without lethal danger, and will also make the cattle normal Condition creates immunity. Pasteur's public demonstration proved that his method can make cattle immune, which caused a huge sensation. It was quickly recognized that his general approach could be used for the prevention of many other infectious diseases.

Pasteur himself invented a method of human immunity based on his world-renowned achievements, which made people immune to the dreaded rabies after vaccination. Since then, other scientists have also invented vaccines against many serious diseases such as typhus and polio.

Pasteur is an exceptionally hardworking scientist. There are still many small achievements in his merit book. It was his experiments, not anyone else's, that convincingly proved that microorganisms did not occur naturally. Pasteur also discovered an anaerobic life phenomenon, in which certain microorganisms can survive in the absence of air or oxygen. Pasteur's research results on silkworm disease have great commercial value. One of his other achievements was the invention of chicken cholera, a cholera vaccine for poultry. Pasteur died near Paris in 1895.

People often compare Pasteur with Edward Jenner, the British doctor who invented the smallpox vaccine. Although Jenner's work was 80 years earlier than Pasteur, I think Jenner is far less important than Pasteur because his immune method is only effective for one disease, and Pasteur's method can and has been used for many diseases Prevention.

Since the mid-nineteenth century, life expectancy in many parts of the world has roughly doubled. Throughout human history, this huge increase in human lifespan may have a greater impact on personal life than any other invention. In fact, modern science and medicine truly give a second life to everyone we live in. If this extension of life can be fully attributed to Pasteur's work, I would not hesitate to list him at the top of this book. Pasteur's contribution is so important that the greatest achievement of the decline in mortality over the last century should no doubt be attributed to him. As a result, he was among the best in this volume. Pasteur has carried out a number of exploratory researches throughout his life and achieved significant results. He is one of the most accomplished scientists of the 19th century. He devoted his whole life to proving three scientific problems: (1) Every fermentation is due to the development of a micro-bacterium. The French chemist discovered that heating can kill those annoying people who make beer bitter Microorganisms. Soon, the pasteurization method was applied to a variety of foods and beverages. (2) Each infectious disease is the development of a micro-organism in the organism: Pasteur saved the French silk industry by discovering and eradicating a bacterium that invaded silkworm eggs. (3) Microbes of infectious diseases can reduce their virulence under special culture, and make them change from germs to disease-preventing medicines. He realized that many diseases were caused by microorganisms, so he established the theory of bacteria.

Major vaccine developed and marketed by Sanofi Pasteur

1934: Tetanus vaccine 1941: Diphtheria, tetanus, pertussis vaccine 1947: Influenza vaccine 1950: Yellow fever vaccine 1955: Live attenuated polio vaccine developed by Sabine 1958: Diphtheria, tetanus, pertussis and polio vaccine 1960: Tuberculin polysaccharide vaccine 1960: Measles vaccine 1962: Sabine oral polio vaccine 1970: Rubella vaccine 1973: Sabine oral polio vaccine (Vero cells) 1974: Meningitis A vaccine 1975: A + C Meningitis vaccine rabies vaccine (human diploid cells) 1979: Salk injection of polio vaccine (Vero cells) 1980: rabies vaccine (Vero cells) 1981: hepatitis B vaccine 1985: measles, mumps, rubella triple vaccine 1987 : Hepatitis B vaccine (using genetic technology) 1987: Diphtheria, tetanus, pertussis, polio and Haemophilus influenzae type five vaccine 1988: Typhoid vaccine (polysaccharide purification) 1992: Haemophilus influenzae vaccine 1992: Broken Tetanus, Diphtheria and Acellular Pertussis Triad 1996: Hepatitis A Vaccine 1997: Diphtheria, Tetanus, Pertussis, Polio and Haemophilus influenzae B

2001: Combined hepatitis A and typhoid vaccine

· Carl Pauling

Linus C. Pauling (1901.2.28-1994.8.19), is a famous quantum chemist in the United States. He is very rich

Linus Karl Pauling

The spirit and innovation spirit, constantly develop marginal disciplines, has made achievements in many fields of chemistry, is the greatest chemist of the 20th century. He has won the Nobel Prize twice (Chemistry Award in 1954, Peace Award in 1962) and has a high international reputation. He is the only scientist in the world to have won the Nobel Prize twice.

Major achievements

In the nearly one century of Pauling's life course, he participated in and experienced many major scientific discoveries in the history of science in the 20th century, with outstanding results: the first comprehensive description of the nature of chemical bonds; the discovery of the structure of proteins; and the etiology of sickle cell anemia; Participated in the research of revealing the structure of DNA; hosted some military scientific research projects during the Second World War; promoted X-ray crystallography, electron diffraction, quantum mechanics, biochemistry, molecular psychiatry, nuclear physics, anesthesiology, immunology, Development of disciplines such as nutrition.