Chemistry Definition and 346 Discussions

Chemistry is the scientific study of the properties and behavior of matter. It is a natural science that covers the elements that make up matter to the compounds composed of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during a reaction with other substances.In the scope of its subject, chemistry occupies an intermediate position between physics and biology. It is sometimes called the central science because it provides a foundation for understanding both basic and applied scientific disciplines at a fundamental level. For example, chemistry explains aspects of plant chemistry (botany), the formation of igneous rocks (geology), how atmospheric ozone is formed and how environmental pollutants are degraded (ecology), the properties of the soil on the moon (cosmochemistry), how medications work (pharmacology), and how to collect DNA evidence at a crime scene (forensics).
Chemistry addresses topics such as how atoms and molecules interact via chemical bonds to form new chemical compounds. There are two types of chemical bonds: 1. primary chemical bonds e.g covalent bonds, in which atoms share one or more electron(s); ionic bonds, in which an atom donates one or more electrons to another atom to produce ions (cations and anions); metallic bonds and 2. secondary chemical bonds e.g. hydrogen bonds; Van der Waals force bonds, ion-ion interaction, ion-dipole interaction etc.

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  1. T

    Groundwater Chemistry on an Island

    Good day all! I have a question about groundwater chemistry on an island. We have datasets over the last 40+ years and what can be seen is that the eastern and western side of the island differ from eachother. On the western side there has been a distinct drop in pH over the last decades, and...
  2. C

    I Physics of paper absorbing Water -- Doesn't this decrease Entropy?

    Summary: doesn't this decrease entropy ? Cellulose is known for its hydrophilic quality, which can be explained from the polarity of its hydroxyl groups. We all know water can overcome the force of gravity through a piece of paper you put in the water. Correct me if I'm wrong but this is a...
  3. samy4408

    About Van Der Waals interactions

    Hello, when reviewing the types of chemical bonds i was a little bit confused about van der waals interactions, in the definition we talk about momentarily disproportion of electrons that provoke a dipole , and then i read that also include hydrogen bonds . I am a bit confused about van der...
  4. samy4408

    Searching for a reliable resource to practice IUPAC nomenclature

    Hello, I just learned the bases of IUPAC nomenclature and I couldn't find a good and reliable resource for problems to practice. if you know one please share it with me . thanks.
  5. abudif1997

    Is this backed up by chemistry or is it a scam?

    Hey guys, not sure if this is the right place for it, but hoping someone can share some chemistry insights on this. I am about to buy some reverse osmosis water filter for my home. However the seller is trying to sell me; Far infrared balls, Mai fan balls, Tourmaline ceramic balls, Alkaline...
  6. E

    Chemistry Conformation Stability of Ethane-1,2-Diol

    Hello there, My attempted explanation/solution is : “Torsional strain is caused by the tendency of the electron clouds in the interacting groups to repel each other, making it relatively difficult to rotate a group towards and through another group, as the repulsive force provides resistance to...
  7. A

    How can vinegar attenuate the pain of a bee sting? (acid base reaction)

    Hello, I have been working on this subject but I am not sure how to deal with it. I am looking to prove how can vinegar attenuate the pain of a bee sting. I have chosen a specific vinegar that is of 6° and 50 ml and Know the molecular weight of acetic acid is 60g/mol. The bee sting contains...
  8. M

    Hypothetical stable isotope of Promethium?

    Say one was to create an artificial stable isotope of Promethium as it has predicted applicable properties. What would it’s number have to be? I know Promethium-147 is semi-stable.
  9. samy4408

    Chemistry Calculate the molar solubility of (CaCO3) with (Ks = 5*10^-9) in water and in a solution of (NaCO3)

    hello , i am solving a problem about solubility and the solution seems weird to me , the problem is the following : we are asked to calculate the molar solubility of (CaCO3) with (Ks = 5*10^-9) in water and in a solution of (NaCO3) with a concentration of 0,1M, knowing that (NaCO3) is totally...
  10. N

    Pourbaix diagram and current voltage curve

    I have a chemistry project and my research question roughly translates to: What is the effect of the different metals electrolytic nature on iron corrosion? (In french: Quel est l’effet de la nature électrolytique de différents métaux (cuivre, aluminium, magnésium) sur la corrosion humide du...
  11. Anmol Dubey

    Identifying the carbon from C13 NMR spectrum

    The molecule is p-phenetidine
  12. samy4408

    Something that doesn't make sense to me about calculating the pH

    Hello , the problem that i refer to is present when we try to calculate the pH of a solution without any assumption. in a lecture entitled "calculating the pH of a strong acid/base solution " after adding a certain amount of HCl in water we are asked to calculate the pH (the amount of HCl and...
  13. samy4408

    A question about chemical equilibrium

    Hello we learned about the chemical equilibrium and how to write it's formula in the case of liquid and gaseous phase , what about a reaction involving different phases ? like this one : how do we write the formula for the chemical equilibrium ? do we just ignore the carbon ,is there any rules...
  14. Vanillasyrup

    Chemistry Bond length

    I really need help with this.
  15. samy4408

    About oxidation and reduction in organic Chemistry

    We studied in chemistry that the concept of oxidation and reduction is the exchange of electrons between two chemical substance ,but when i started to study organic chemistry i saw that when we talk about for example the oxidation of a compound it can loss atoms and change his constitution...
  16. G

    Programs MSE --> Chemistry (BS)-->?

    Just to keep this from being a long post: I went to a local CSU for Materials Science and Engineering in the fall of 2018 after graduating high school in the spring of 2018. I really like learning about everything that makes up the world around me, and why things are the way they are, and in...
  17. E

    Chemistry Thoughts on Introduction to Chemistry fourth Edition by Bauer?

    Hi there, I am currently reading introduction to Chemistry fourth edition by Bauer, Birk, Marks. what do you guys think about this book? is it a good book? I am doubting the quality of the book because I found one wrong statement about the reaction of Alkaline Earth Metals. It said "Alkaline...
  18. StarChem

    Neutralizing acidified lakes

    I calculated it and found that is approximately 610Kg needed of CaCO3 to bring the lake pH to a neutral level. Is my calculation right 1st :)? Then if this is right, 610kg of CaCO3 is not that much in a matter of cost or weight to help the bio-life of the lake. I'm wondering if we are applying...
  19. D

    Chemistry Reference book on catalytic mechanisms of enzymes

    Hi everyone, I'm curious if anyone knows of a reference book on enzymes that discusses each enzyme's catalytic mechanism(s). I've consulted several books that explain the different categories of enzymatic catalysis but I'm looking more for an encyclopedic reference that explains such...
  20. Sophrosyne

    Medical Tensile strength of cell membranes

    The structure of the cell membrane is depicted as being formed from a bilayer of phospholipids with their hydrophilic portions pointing outwards and their hydrophilic portions facing each other. But as I look at the histology of the epithelial layer of the epidermis or mucous membranes, I am...
  21. ayans2495

    Finding the final temperature of a mixture of ice and steam

  22. S

    Chemistry Drawing resonance structure for this O-CH2 ion

    ion shown: My answer: the following is the answer of the question: I identified the major contributor correctly, but the resonance structures, but the second resonance I drew is missing in the answer sheet. Can anyone tell me why the second resonance structure is not part of the answer...
  23. S

    Chemistry Drawing resonance structure for SO42

    I was told that there are six resonance structures for SO42-, as shown below. I am wondering why this structure with single bonds is not one of the possible resonance. I understand that it is unfavorable as the formal charges are spread out over all four atoms, but shouldn't is still be a...
  24. Epsilon Eridani

    Turning oxygen into fluorine in our atmosphere

    Summary:: Hypothetical discussion of a method to turn oxygen into fluorine through the use of another chemical and also discussing the biological effects of fluorine. Hello, I'd like to start this by saying my knowledge of chemistry is extremely basic. I barely graduated chemistry in high...
  25. favphysics

    Chemistry Where can I buy Solutions Manual of Whitten’s Chemistry by Whitten

    Hello everyone! Where can I buy Solutions Manual of Whitten’s Chemistry by Whitten & Davis | 10th edition ? Thank You!
  26. Ygggdrasil

    RIP Mario Molina, Nobel Laureate for work on ozone layer Molina shared the 1995 Nobel Prize in Chemistry with Paul Crutzen and F Sherwood Rowland "for their work in atmospheric chemistry, particularly concerning the formation...
  27. DrClaude

    2020 Nobel prize in chemistry
  28. dcybroz

    What materials are the most resistant to chemicals?

    Ok so im building a fume hood What materials are the most resistant to chemicals that are also cheap? also what cfm fan can I use to suck out the air? (asking for someone knowlageable) cats
  29. S

    Chemistry Is this the right way to approach solubility problem?

    Is my work and the answer correct? If not, how should I approach this problem? Thank you!
  30. Rzbs

    Lithium-ion rechargeable batteries

    I want to know how a lithium ion rechargeable cell works with very basics details. I don't need a simple describtion like most of the websites and videos. I need a resource that explain the chemistry and physics of a Li ion cell from very basics of knowledge. Could you please introduce such a...
  31. ambivalent_chemicist

    Programs Major in Chemistry or Physics?

    As with probably a lot of pure science undergrads, my dream goal is to become a researcher, academia or industry. As far as I know at the moment, I'm interested in the area of research that straddles physics and chemistry, and I'm not sure which one I should major in. Should I major in chemistry...
  32. S

    Trying to Understand Ionization

    It will try to produce a neutral atom but it depends on the amount of energy that electron is shot at the atom, if it is great enough energy for ionization it will produce cation, If it is not enough for ionization it will make a neutral atom or anion, I think.
  33. S

    Chemistry Electron Affinity

    I think that an electron adds up in the valance shell of an atom because an atom tends to achieve the nearest noble gas configuration. But I dont understand how and why electron enters the valance shell. Energy is released when an electron adds up in the valance shell. But why is energy...
  34. C

    Programs Double Major in Electrical Engineering and Physics?

    I’m a freshman in undergrad and I currently attend the University of Illinois at Chicago. I major in electrical engineering but I have an extremely strong interest in physics, chemistry, and materials science. UIC doesn’t have a materials science program, but George Crabtree, a highly cited...
  35. osg99

    Creating A Ligand // Selective Androgen Recepetor Modulator (OSTARINE)

  36. H

    I'm confused (Acids/Bases)

    The question says: A solution of highly acidic HA is given, with a molarity of 1M. Is it true that [A-]>[H3O+] or not? I simply don't understand why the hydronium is mentioned and i don't know how to find the molarity of these two individually.
  37. fbeaker

    Spectrophotometric Determination of Fe2+ (Beer's Law)

    I am having troubles with a question I have to do for my chem pre-lab. The question is: The following intercept and slope were obtained for a Beer’s Law plot of Absorbance versus concentration (mg Fe2+/L). Slope = 0.2200 L/mg Fe2+ Intercept = 0.004 Calculate the percent (by mass) of iron in the...
  38. M

    Chemistry Ideal Gas Problem

    Hello guys. I really try to understand the problem, can you please help.
  39. Navin

    Chemistry Compare the Bond lengths of IO2F2 and IOF3

    Okay So our Chemistry Professor gave us the answer as the following IO2F2 has a larger bond length than IOF3 The reason being is once you draw the structures of the compounds IO2F2 has more number of double bonds that the later hence it shall have more p charecter than IOF3...hence it will...
  40. O

    I Efficiency of computers vs. brains

    Hi, I’m an undergraduate student interested in cognitive processes. I’m about to ask a very interdisciplinary question, and so hopefully I can find a physicists that can take on the challenge. What is the fundamental reason behind why modern electronic computers (transistor computers) are...
  41. M

    Chemistry What is the ratio of pH=Pka-1?

    I think it is 1:10 but I am not sure the meaning of PKa -1, can someone explain it please.
  42. TonyKonya

    Specific Heat at High Temperatures

    I am working on some simulations to determine pressures for extremely high-pressure combustion events. The temperatures in these events can range anywhere from 3000 K to 6000 K. In order to do this I need to find valuers for specific heats of gases at these temp ranges as I know they vary to a...
  43. P

    Emission Wavelengths

    Problem Statement: A sample of excited atoms lies 3.031×10^−19 J above the ground state. What is the emission wavelength of these atoms? Relevant Equations: E=hc/λ λ=hc/E I'm stuck on the first part. i.e; something / 3.031x10^-19J
  44. bagasme

    Courses Introductory Chemistry Requirement for Physics Majors: Why is it Mandatory?

    Hello, I looked into lists of subjects/courses for Physics Major, and I surprised that Introductory Chemistry is in the list, as mandatory course. I suspect that Molecule and Solids and Nuclear Physics chapter have to do with chemistry Why is it mandatory to take Introductory Chemistry course...
  45. Fabrizio Vassallo

    What is the composition of the Earth's exosphere?

    Hello! My name is Fabrizio, I'm a high school student doing some research on the atmosphere. Right now, I'm trying to figure out how much matter escapes into space via Jean's Escape. I've found several formulas, all of which require me to know what the amount of particles per m3 of a certain...
  46. trienebutdiene

    2020 US National Chemistry Olympiad

    Summary: Thread for discussing the USNCO and how to do well on it. More specifically, tips for doing well on the national round and making the study camp are welcome. Anyone with experience with the olympiad is welcome to post, especially previous study camp qualifiers and honors/high honors...
  47. K

    Decomposition reaction for theophylline, hexobarbital natrium

    Hello! There is a problem to write chemical reactions that goes with substances if they are not stored properly. For example theophylline should be saved from light and though I am trying to find its’ reaction with hv(light) but failed. Please help with some good reference Many thanks in advance