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. N

    MHB Chemistry: Balancing Redox reactions

    What do i have wrong here for my chemical equation? Seems to be right but my homework won't accept it. Balance the redox reaction occurring in acidic solution. Sn(s)+MnO−4(aq) → Sn2+(aq)+Mn2+(aq) Express your answer as a chemical equation including phases. 5Sn+2MnO−4+16H+→5Sn2++2Mn2++8H2O...
  2. P

    Testing Should I CLEP out of Chemistry?

    Background: 1st year freshman, CLEPed out of Cal I since couldn't take the class 1st semester (scored 79/80, so think that my knowledge in the subject is good enough). So, my degree plan requires that I take General Chemistry I and II. However, I am not the biggest fan of Chemistry and would...
  3. A

    Need an explanation -- Consider pure water separated from....

    Consider pure water separated from an aqueous starch solution by a semipermeable membrane, which allows water to pass freely but not starch. After some time has elapsed, the concentration of starch solution a. will have increased b. will have decreased c. will not have changed d. might have...
  4. S

    What are possible polymer chemistry experiments?

    I was wondering if there were any possible experiments that I can conduct in a high school lab setting.
  5. Q

    Nuclear Engineering and Chemistry Concern

    Does nuclear engineering require a lot of chemistry? Chemistry is not my strongest subject simply because I chose to skip it in high school. So I just wanted to know if it was heavily ridden with chemistry. And if so what topics do I have to look forward to. ugh...
  6. C

    Chemistry Chemistry Professionals -- I have an Interview -- help please

    Hey everyone, I am a recent chemistry undergrad and just got an interview for a lab supervisor at a local college (undergrad) I know I will have to assume a lot of responsibility, and I am prepared for that. However, being my first professional opportunity, I have no idea what to expect. I know...
  7. N

    Energy Change Nuclear Chemistry

    Homework Statement Determine the energy change, delta E, in J when 500 g of 229/90 Th undergoes the following nuclear reaction: 229/90 Th --> 225/88 Ra + 4/2 He The nuclear masses in amu or g/mol are: Th-229: 229.03175; Ra-225: 225.02360; He-4: 4.00260 Homework Equations delta E = deltam(c)^2...
  8. S

    What are some good polymerization chemistry experiment ideas

    I'm very interested in researching polymerization chemistry for my school science fair. All the ideas I have are either too expensive or not complex enough.
  9. G

    Zinc+Iron+Acetone+Hydrogen Peroxide

    When I added a zinc plated iron ball into the acetone-peroxide solution, they zinc started bubbling. The solution turned whitish. Then after leaving overnight it became grayish with orange red foam on top
  10. P

    Can a Journalism Background Lead to a Successful Career in Earth Sciences?

    Hi everyone, My details: Age: 26 Education: Bachelor's in Mass Media; Post-graduate Diploma in Journalism Work ex: 5 years for an international news agency covering pharmaceuticals and healthcare. I loved science in high school and was great at it, but couldn't continue due to some unavoidable...
  11. Arthur Donovan

    What Exactly Do I Need To Study (Chemistry)

    Hy , i m a chemistry beginner I m trying to be autonom in everything And i want to be able to make my own substances. For instances Chloroform , glycerine etc And many other basic substances So what do i need to study in order to make these substances correctly in a lab .
  12. L

    Chemistry Chemistry: Molecular Iodine and Atomic Iodine

    So I just had a question about calculating moles atomic iodine when you have the moles of molecular iodine. In the chemical equation IO3-(aq) + I-(aq) + H+(aq) = I2(aq) + H2O(l) Would the moles of atomic iodine be equal to the moles of the molecular iodine? or would the moles of atomic iodine...
  13. ItchyFungus

    Programs Need help with majoring in either chemistry or physics

    I am interested in nuclear reactions, so the ultimate goal is to get into either nuclear physics, or nuclear chemistry. The thing is, I am torn between the two in which one to major in. Should I major in chemistry or physics first? The goal is to work alongside a nuclear physicist or chemist as...
  14. Preston Feagan

    Looking to dissolve plant matter without affecting rubber.

    Hello! I'm having a bit of an issue here, and I came across this site while searching on how to dissolve plant matter. The thread I found had some ideas, but said a reason would be needed before any concrete advice could be given. So here's my request - I need to instantaneously dissolve plant...
  15. R

    Question about Organic Chemistry and Physical Chemistry

    Hi. I have a question about Organic and Physical Chemistry. I have already finished General Chemistry I and II and got decent scores on both of them (B on both of them). I am interested in taking Organic Chemistry, then Physical Chemistry afterwards. I know that both are different from General...
  16. Natsu1993

    How to prepare 50mM Na2HPO4/H3PO4 buffer, pH 4.5

    The have to prepare the buffer but I really don't know how. Is the any formula for the buffer preparation? Ps. Sorry but one more thing, what does the "/" between Na2HPO4 and H3PO4 mean?
  17. cookiemonster13

    Oxygen formation in Earth water

    I always wondered why they say water and photons created the first microbes which later evolved and produced oxygen which filled our oceans and atmosphere. So how could have water existed without oxygen? I tried to look up and came up with different explanations, but it doesn't make sense.
  18. A

    Making a graph of CuSO4 concentration vs volume of solution

    Homework Statement Hi, I don't even know where to begin with this type of graph. It does say that the graph should be a straight line. This is for one of my questions for my lab that I am completing. This is the link of mytable with info...
  19. T

    MHB Troubleshooting Mastering Chemistry: P4 + O2 → P2O5

    I am stuck on this chemistry problem using Mastering Chemistry to do my homework. This is the problem. When I enter the answers it keeps saying is that "One or more of the units you entered is not recognized." **My Answers**For part A my answer was 426 g P2O5 and for part B 369 g...
  20. R

    Is Physics Forums the Ultimate Destination for Chemistry Enthusiasts?

    I really like Chemistry. I like physics but not as much as physics. Is it likely that Physics Forums will intrigue me? I found this website trying to find the model on how to solve a chemistry problem but I really enjoy the overall quality of website and was thinking I would give it a shot.
  21. A

    Enflurane (CHFClCF2OCHF2) Lewis structure

    So I keep getting this problem wrong and I don't know what's wrong. The structure I came up with is attached. If anyone can help I'd really appreciate it!
  22. betweenthelens

    Courses Geometry and Chemistry Together

    Hello, My 14 year-old son just started ninth grade. Last year in eighth grade in middle school, he completed a Regents ninth grade level science (living environment) class and its corresponding lab and a Regents ninth grade level advanced algebra class. He passed both Regents exams both of...
  23. CMATT

    Organic Chemistry Recrystallization

    Homework Statement Why is ethanol a bad choice for recrystallization of phthalic acid? 2. The attempt at a solution I know phthalic acid is very soluble in water, so water is a great candidate to recrystallize phthalic acid. I also know water and ethanol are not miscible. But I don't know how...
  24. Vivan Vatsa

    Difference between many chemically related terms?

    In chemistry, chemical bonding is a very important topic. What I can't really understand is the interrelation of different theories which explains the same kind of thing, like for structure of any compound there are theories like Valence bond theory or VSEPR or molecular orbital theory. I am...
  25. Z

    Why isn't the temperature of this vapor T_sat?

    A rigid tank with a volume of 2.00m3 contains 5.77 kg of saturated liquid-vapor mixture of water at 75 deg C. Now the water is slowly heated. Determine the temperature at which the liquid in the tank is completely vaporized. Why isn't the temperature just 75C? If it is already a mixture in...
  26. micromass

    Other Introduction to physics and chemistry

    Hello everybody. First of all I want to make clear that this is not for me. I'll try to describe the kind of thing I want and the background that can be assumed. I am look for introductory physics and chemistry books. The background in physics and chemistry is zero. So the person this is for...
  27. A

    Organic chemistry- adding amine group to benzene

    Is it possible to do a Friedel-Crafts reaction on a benzene and get a substituent on the benzene ring from that, and then afterwards add an NH2 group ortho? I know you can't add NH2 first and then do Friedel-Crafts because anilines cannot undergo Friedel-Crafts. Please advice. Thanks in advance.
  28. doulyftbruh

    Change in Gibbs free energy at equillibrium

    I understand that the change in Gibbs Free Energy at equillibrium is 0 and this leads to the equation -deltaH=TdeltaS. My questions here is that if a reaction is at equillibrium, how can there be any change in enthalpy or entropy at all? Why wouldn't these terms be 0?
  29. S Aditya

    About the Orbital Dipole Moment

    I was going through the chapter Chemical Bonding in one of the books and found something about orbital dipole due to lone pairs. In each diagram the orbital dipole due to lone pair was directed from the central atom to the end of the hybridized orbital (lone pair). Why is that so?
  30. A

    Vapor Pressure In Closed Cylinder

    Hi There, I am trying to understand if I have a vacuum in the below scenario or simply just really low pressure. A pump supplies a pipe with a constant supply of water at one end (Point A) the water discharges several kilometers away at some lower elevation (Point B). At "Point A" a valve...
  31. L

    Finding dissociation constant for f-

    If I'm given the dissociation constant for HF, how would I find the dissociation constant for F-? Thanks in advance.
  32. L

    Calculating amount of H2SO4 needed for dilution

    Homework Statement How much 4.00M of HCl is required to make 100ml of 0.400M HCl? Homework Equations M1V1 = M2V2 The Attempt at a Solution Its (4.00M)*(xL) = (0.400M)(0.100L) I think its 0.005L but the possible answer (multiple choice) say otherwise...
  33. S

    Stoichiometry: Identify the metal and formula of it

    Homework Statement All of the lanthanide metals (La through Lu) react with HCL to form compounds having eithe the formula MCl2, MCl3, MCl4, (where M represents the metallic element). Each metal forms a single compound. A chemist has a 0.250g sample of a lanthanide metal, and she wishes to...
  34. schmikah

    Nuclear Mechanic/ Engineering Laboratory Technician

    To everyone reading this, hello. I'm obviously new but bursting with interest in nuclear plant design. I already have six years of experience in Naval nuclear power plant operation and maintenance, so if anyone can clue me into the wider world, I would be eternally grateful.
  35. H

    Other Want to be an engineer, but do research on the side?

    So, I really want to be an Aerospace Engineer, but I also love chemistry, physics, math, and etcetera. Most of what I love tends to be application focused, rather than pure. Regarding chemistry, I really like synthetic physical organic stuff; especially geometrically strained compounds and...
  36. L

    Good compact chemistry overview for scientists

    Can someone recommend a good chemistry overview/ review? Some pdf document perhaps, not more than 200 pages or so. Notes that do not assume you are complete beginner, but you have a science (physics) background. That gives brief summaries and the highlights of all the topics that are dealt with...
  37. Flare12

    Courses Chemistry, Biology, or Physics?

    Hi everyone! In just about a month, I will be starting my IB courses in junior year high school. I have chosen Math SL, along with Economics Hl, Biology HL and Chemistry HL. However in the past few days I suddenly realized how I also really like physics (especially quantum mechanics and natural...
  38. K

    Prolonged contact between HCl and alkanes

    I've verified that there is no obvious reaction between hydrochloric acid and simple alkanes (roughly C4-C12) over short timescales; they simply settle out with the heavier HCl on the bottom and the lighter hydrocarbons on the top, with no apparent heating or changes in general properties (as...
  39. Quentin_alex

    Chemistry Chemistry, material science, and med school

    Hello, I am currently a materials science major going into my junior year. I recently gained interest in medical school (specifically anesthesiology and radiology) However, I do not know if this is going to be the plan yet for me. I am thinking about changing my major to chemistry, so that I...
  40. N

    Is There a Way to Create Non-Flammable Fireworks?

    With so many advances in technology and science, I find it difficult to believe that no one has cracked the code on non-flammable 'fireworks'-- something that still gives us the same bang for our buck without the ash and firestarters falling back to the earth. So, here's a challenge: Present an...
  41. E

    Chemistry Level of statistics required in Process Chemistry and ChemE

    Question: So I hold a Bachelor's degree in Chemistry and have just started a M.S./Ph.D. track in Chemical Engineering. My dream job is in mineral processing (the biggest dream is with an asteroid mining company), but I understand that the school I'm going to is heavily focused on drug discovery...
  42. MickeyBlue

    Material balance with a reaction (chemical engineering)

    Homework Statement Felder & Rousseau 4.73 (p. 184) A mixture of propane and butane is burned with pure oxygen. The combustion products contain 47.4 mole % H2O. After all of the water is removed from the products, the residual gas contains 69.4 mole% CO2 and the balance is O2. What is the mole...
  43. V

    Studying Physics, Chemistry or Nanotechnology?

    I am an university student, and I have the opportunity to choose the career in semester 5. Now, I am in semester 4 and I am indesicive between Physics, Nanotechnology and Chemistry. I am very afraid, It could be possible that you say me your experiences. I am interesning in materials, energy and...
  44. sevenperforce

    Finding reaction products in reduction chemistry

    Contrary to potential appearance, this is not homework. I've been out of college for a long time now. Just working on a project with my kids and I'm trying to approach specific energy of these reduction reactions from the theoretical side, mostly so I know what sort of safety precautions to...
  45. oysterberg

    Studying Sc Neurobiology Student Seeking Scientific Foundations

    Hello everyone, I've never used PF before, so I'm not exactly sure I'm posting in the right place. Anyway, here's what's going on : I'm currently preparing a Master's in neurobiology. I stopped studying sciences (i.e., physics, chemistry, maths) in high school, but somehow managed to catch up...
  46. R

    I am sure I am doing this Acid/Base problem wrong

    What is the pH of a solution made from 34.6 ml if 3.45*10^-4 M of H2SO4 added to 41.7 ml of 4.56*10^-4 M of Al(OH)3? I know how to find H+ and OH- and pH I also know how to use x mol / L, but I cannot get them to click together. Everyone keeps telling me to use RICE but my professor never...
  47. upender singh

    Counter flow diffusion flame simulation using Fluent

    Hi, I am trying to model a counter flow diffusion flame using ansys fluent with fuel/oxidiser as methane/air. The problem is that the flame temperature(800 K) is much lower than what it should be(>1600 K). I am using Non premixed combustion module with steady diffusion flamelet and adiabatic...
  48. S

    Determining Rate Constant for Hydrolysis of Ethyl Lactate with Acid Catalysis?

    Homework Statement Hydrolysis of ethyl lactate Determine the value of the rate constant for the hydrolysis of ethyl lactate from the following data. Mass of ethyl lactate (grams): 0.5956 Concentration of stock HCl solution (M): 0.01023 Standardization titration volumes (of NaOH): Run...
  49. S

    Programs Struggling to decide on MSc following chemistry degree

    I was hoping for a bit of advice about the options I'm considering, or if anyone knows of a good place I can ask the same question, that would also be appreciated. I'm considering a few different masters degrees but there isn't really one that I think I'd enjoy significantly more than the...
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