What is Chemistry: Definition and 993 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 Alkaline buffers

    THe answer is supposed to be (B) but I'm not understanding properly I initially chose A - to form an alkaline buffer, the # mol of acid should be half of this. But this doesn't seem to be the case I don't understand why the mol of base in this case should be 5x the mole of acid your help is...
  2. jedishrfu

    New Insight into the Chemistry of Solvents

    https://www.newsweek.com/basic-principle-physics-wrong-oxford-university-scientists-say-1874984
  3. R

    In the contact zone between geology and physics...

    My name is Ron Werner, Dutchman, living/working in Norway since 1992. My main interest is geology and I have worked for several museums and mineral-dealers during my life. Since 2000 I have worked for the Evje og Hornnes geomuseum Fennefoss in Evje, in the south of Norway. It is a small museum...
  4. Ranger1222

    Engineering Building a peripheral for obtaining data from water

    I'm working for a project with a goal of analyzing data obtained from a device that extract data from bodies of water, such as bacterias found, the chemical levels, etc. I've been instructed to use existing equipment for it to work. What I've been recommended to use include: bateries, solar...
  5. G

    Process Control (transfer function) problem

    TL;DR Summary: transfer function Hello, I have a doubt on this exercise from my post graduation course: ____________________________________________________________________________________________________ The transfer funtion of a series RL circuit is given by: Determine the answer y(t) for...
  6. walkeraj

    Just a middle-aged amateur person into physics

    Degree in chemistry and at one point was a physics and mathematics double major, but life intervened. Never got to finish but still read and work on novel amateur theory. At least, what I would call novel and amateur. My focus is on putting together theory on space-time and quantum field...
  7. L

    Physical Chemistry

    I tried to calculate the energy of an H-Atom with the one electron integrals. I tried to solve them numericaly but it didn‘t worked. Thats why I am hear.
  8. E

    Understanding CVT Fluid Viscosity and When to Replace: Expert Insights

    I went to Subaru for period maintenance checkup. They told me the car was due for CVT fluid replacement which was done every 5 years or 40,000 miles. It's already 7 years even if the mileage is only below 20,000 miles so I let them go ahead. The service advisor told me as time passes, the...
  9. dddd

    What Makes Iodine So Fascinating? Exploring the World of Elements

    I’m currently fascinated by the the element iodine. Hoping to find out more about this topic, and other elements.
  10. cutielollipop

    Chemistry Enthalpy of Formation of ZnO lab

    Experiment equation: Zn(s) + 2HCL(aq) -> 2ZnCl(aq) + H2(g) a) If the the mass of zinc solid used was doubled, what effect would this have on temperature change? Answer: if mass of zinc increases, there will be an increase in zinc particles which increases the collisions between particles and...
  11. 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...
  12. 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...
  13. B

    How can I chemically regenerate my car's catalytic converter?

    Hello all! I've joined your forum here because I have some (what I believe are probably) basic but precise chemistry questions and I don't know any chemists or chemistry professors (or even chemistry students) whom I can ask. Recently, my car's catalytic converter's been giving me some trouble...
  14. 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...
  15. K

    How do I calculate the rate constant units for 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...
  16. 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...
  17. 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)
  18. 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?
  19. 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...
  20. 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...
  21. L

    What is the Best Resource for Finding Answers to Chemical Reactions?

    Hello! I am Logan, I am a student and i like chemistry! I came here because I was searching for an answer for a reaction I did but found nothing elsewhere.
  22. 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...
  23. 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
  24. 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...
  25. 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...
  26. 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...
  27. 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...
  28. 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...
  29. 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...
  30. 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...
  31. 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...
  32. 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...
  33. 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
  34. 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?
  35. 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...
  36. 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...
  37. inspacewithcallisto

    Misc. Can Ethyl Acetate be Used to Remove PLA from Plaster of Paris Molds?

    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...
  38. 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...
  39. 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.)
  40. MichaelBack12

    Studying Preparing for Organic Chemistry: Tips for Reviewing Inorganic Chemistry Concepts

    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?
  41. 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...
  42. 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...
  43. 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...
  44. 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...
  45. 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.
  46. 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...
  47. 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...
  48. 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...
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