What is Chemistry: Definition and 975 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. S

    Chemistry Determination of the molecular structure of two organic compounds

    I've figured out that both compounds have 4 unsaturations. The fact that they are insoluble in water makes me think they might have a benzene ring. When bromine water is added (I found out online that it's Br2 in water), perhaps some hydrogens from the benzene ring might be replaced. However...
  2. T

    Calcium Chloride based dessicant

    Hello everyone. I would like to experiment with solar air conditioning, wich may work as a massive dehumidifier. I have the idea of making a suspension/solution of Calcium Chloride and / or some sort of Lithium dessicant salt in some sort of oil, run between a solar boiler to evaporate water,on...
  3. PhysicsInterest

    Is there a greater answer for naming D-Block elements the way they do?

    Ok so I’m going into my second year of college and I’m starting to learn more advanced chemistry (pray for me🙏) I’m currently on the topic of D-Block elements and I was already aware of electron configurations and how to write them out… however what I have never come across prior was the use of...
  4. K

    What are the rate constant units in this equation? (excitation by electron impact)

    Hi, I struggle to calculate the unit of the rate constant that is [m^3/sec] rate constant of excitation by electron impact is as follows: where, e=charge of electron [Coulomb], me=mass of electron [kg], ε=energy [eV], σe(ε)=cross section for electron impact [m^2], f(ε)=electron energy...
  5. Z

    Chemistry How do we know ##BF_3## has Lewis structure but ##Al_2S_3## does not?

    The first thing we notice is that we have a metal and a nonmetal, so we would think about an ionic model. These elements form the ions ##Al^{3+}## and ##S^{2-}##. These ions form a lattice structure and we get an ionic crystal. But apparently no bond is perfectly ionic or covalent. The...
  6. Hasal

    How did Rutherford prepare the gold leaf for the gold leaf test?

    How did Rutherford prepare the gold leaf for the gold leaf test (at that time)
  7. W

    What books can I use to learn chemistry as a physicist?

    I trying to learn chemistry as a physicist. Any advice? What books would you recommend?
  8. SaketIndra

    Titanium dioxide solution in oil

    Hello everyone, I am seeking assistance in preparing a Titanium dioxide solution in oil. Below are the chemical compositions of the solution: Titanium Dioxide (TiO2): 20% by weight, with the product name Tronox CR828. Solvent/Oil: Isoparaffin, constituting 75% by weight, with the product name...
  9. taimcampos92

    State function question as it applies to Biology/Physiology

    Hi everyone! Hope you all are doing great. I'm currently starting a new course mixed with Chemistry, Biochemistry, and Physics-related to Nurse anesthesia. While reading about State function a question arrived on my team. We all agreed that a State Function "is a property or characteristic of a...
  10. Ako9

    Chemistry Exercise about an aqueous solution (containing a halogen)

    I can't find my mistake, can you help me? I suppose that in 1000g of solution there are 50g of solute and 950g of solvent. Then I find the molality $$m= \frac{50}{MM} \cdot \frac{1}{0.950}$$ So I can find the Molar Mass of the compound using the relation $$\Delta t=K_{cr}\cdot m \cdot i$$ where...
  11. J

    Chemistry Predicting the electron domain and molecular geometries

    I would like to know how can we determine or tell from the diagram that the electron domain is tetrahedral and molecular geometry is bent/ v-shaped? thanks
  12. fluidistic

    LaTeX Most awesome periodic table of the elements in Latex?

    I would like to print a nice PTOTE, written in Latex. So that I could make small modifications before printing it. I have checked on the Internet, but surprisingly couldn't find any really nice one. Ideally, it should contain information like the fusion point, possibly crystallographic...
  13. L

    Admissions DOE SULI Advice For Biology Background - Renewable Energy Development

    Hi Everyone! I am an upperclassmen undergrad of a biol background, with mainly course training in biochemistry and molecular biol, and taken chem like o-chem and a-chem, and introductory physics. I have three short term summer projects at top 5 institutions in the past and in the field of...
  14. G

    Chemistry Help Needed with Chemistry MIT Course Question

    Hello, I have a doubt in a question from a chemistry MIT course: My attempt is attached. The formula given in the lecture is D = Do * exp(-Ea + Delta Gn)/RT However, they don't explain what Delta Gn is, I suppose it is Gibbs free energy, but as the statement doesn't give any other extra energy...
  15. D

    At a Crossroads Between STEM Majors (narrowing interests)

    Hey all, Long time forum lurker here. There's a lot on my mind, but I will do my best to keep it concise: I'm an undergrad chemical engineering student, just starting my junior year. I have found myself at somewhat of a crossroads concerning my career pathway: Originally, my plan was to finish...
  16. BillTre

    Origin of Life Chemistry interview with Bill Martin

    This video is an interview of Bill Martin (Martin wikipedia link) (one of the godfathers of modern origin of life chemistry) by Jitender Kumar about several origin of life issues. He has a lot chemical knowledge and expresses it clearly. Interesting to me, he places the formation of membranes...
  17. K

    Preparing for Grad School: A Organic Chemistry Review

    I’m starting my PhD in Organic Chemistry this Fall. I want to review all of undergraduate Organic Chemistry and I’m trying to develop a plan of attack. I did alright in lectures but not perfectly and did quite well in labs. I don’t want to be bombarded in grad school and want to have a proper...
  18. PhysicsInterest

    Uncovering Your Passion for Chemistry: What Drives You?

    So it’s not so much a question solely based around chemistry as a subject it’s more about you. The individual reading this. I want to know why you have such a great interest for chemistry. Is it just something you find fun?, is it the deeper understanding of the universe you enjoy?, is it the...
  19. V

    What's the chemistry behind a semiconductor?

    This is a confusing subject for me. It's like only getting half of the story. Reading physics but not understanding how it works in chemistry makes it nonsense to me. Imagine we are creating a silicon-based semiconductor. They have covalent bonds between them, with each silicon atom having four...
  20. V

    How to study chemistry as a wannabe inventor?

    I tried to study chemistry on my own for a while, and I came up with a question. You know, the whole point of learning new subject is to learn core principles, and then understand all their outcomes in things around us. And later to come up with new things based on this principles. Say when...
  21. K

    Normalize function - quantum chemistry

    Normalize function f(r) = Nexp{-alpha*r} Where alpha is positive const and r is a vector I was just wondering if the fact that we have a vector value in our equation changes anything about the solution
  22. Half Infinity

    Polarisability versus Nucleophilicity

    In halides, I- is the most polarisable and F- is the least. So shouldn't I- be most nucleophilic ( in aprotic solvent) as its cloud should most easily be distorted and transition state with electrophile should be achieved most easily? Or is polarisability very different from nucleophilicity?
  23. gggnano

    Can I make a rocket by mixing aluminum + iodine (+ water catalyst)?

    Basically it's a well known reaction, many kids on youtube make it for the views: I am thinking, since AlI3 sublimes can it be put in say tungsten bottle (is this even a thing??) and then used as a rocket the same way Na+H2O or HCL+Al rockets are used - the gas escapes? This phase...
  24. agm

    Finding the Equivalence Ratio of Combustion (Methane + Air)

    I'd like to do some experiments with flames at different Equivalence Ratios - but I'm confused as to how I can find the Equivalence Ratio for different conditions. Wiki-article So the stoichiometric balance for Methane + Air is CH4 + 2(O2 + 3.76N2) -> CO2 + 2H2O + 7.52N2 Referencing equations...
  25. inspacewithcallisto

    Misc. PLA and Plaster of Paris

    I'm trying to make a mold because I want to add something to some jewelry. I 3D printed the symbol that I wanted, and tried to make a mold with Plaster of Paris. But I can't take the print out of the plaster, and I don't want to damage it with a knife. I'm thinking ethyl acetate? A quick google...
  26. atyy

    Nobel Prize in Chemistry 2022 (2nd Nobel for Barry Sharpless)

    https://www.nobelprize.org/prizes/chemistry/2022/press-release/ The Royal Swedish Academy of Sciences has decided to award the Nobel Prize in Chemistry 2022 to Carolyn R. Bertozzi Stanford University, CA, USA Morten Meldal University of Copenhagen, Denmark K. Barry Sharpless Scripps...
  27. DaveC426913

    How fast does biological chemistry happen?

    I've seen this before, but it boggles my mind when I try to put it in the context of a boxer practicing his jabs. Just how fast are these individual reactions occurring? (Did I get he right GIF? It's supposed to be the one of muscles contracting.)
  28. MichaelBack12

    Studying Prep for organic chemistry

    Summary: What’s the best way to review inorganic chem in preparation for OC. Assume zero recall on basic college chem. Are there study guides, online courses, etc. for this specific purpose?
  29. 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 each other. On the western side there has been a distinct drop in pH over the last decades, and...
  30. casparov

    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...
  31. 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...
  32. SGKent

    Mystery Stain Solved with Fertilizer Chemistry!

    I mixed some fertilizer based on a soil test. The chemistry contained Ammonium Sulfate prills (NH4)2SO4, Potassium Sulfate prills K2SO4, Superphosphate CaH4P2O8, trace of Manganese Sulfate MNS04, and trace of Boric Acid H3BO3. I mixed it and wiped my hands on the front of a white tee shirt...
  33. 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.
  34. 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...
  35. 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...
  36. 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...
  37. 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.
  38. samy4408

    Chemistry Calculating Molar Solubility of CaCO3: A Puzzling Problem

    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...
  39. Saba_467

    Chemistry projects that I can create at home

    There is no laboratory in my school ,looking for best chemistry project ideas for the 12th class students at minimal cost and that can be prepared at home . need suggestions on this,response would be appreciated
  40. 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...
  41. Y

    Milk + citric acid or pineapple juice formula? (chemistry)

    I have a chemistry project involving milk coagulation under certain circumstances. One of the circumstances is milk combined with citric acid or pineapple juice. I need to find the chemical formula of this reaction.
  42. Anmol Dubey

    Identifying the carbon from C13 NMR spectrum

    The molecule is p-phenetidine
  43. 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...
  44. samy4408

    Organic chemistry: Are all non-aromatic carbon chains aliphatic?

    Are all non aromatic carbon chain aliphatic ?
  45. 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...
  46. A

    Chemistry Degree of Ionization in Chemistry Textbooks

    Can someone please tell me what is the chemistry textbook that available about degree of ionization? I use Chemistry the Central Science textbook by Brown. Unfortunately I couldn't find about degree of ionization in this textbook. Degree of ionization is studied in undergraduate of Mechanical...
  47. Mayhem

    [Quantum Chemistry] Generalized wave function in covalent bonding

    Is there a general expression for the wave function $\psi$, which describes the electronic properties of an arbitrary covalent bond? For example is it equal to some sort of trigonometric expression?
  48. Vanillasyrup

    Chemistry Help with This: A Guide for Finding Solutions

    I really need help with this.
  49. 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...
  50. 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...