Chemistry Definition and 993 Threads

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. C

    What Is the Equilibrium Concentration of H2(g) at 1000°C?

    Homework Statement consider the following reaction: 2H2O(i) <-> 2H2(g) + O2(g) kc=7.3*10^-18 at 1000oC The initial concentration of water in a reaction vessel is 0.055 mol/L. What is the equilibrium concentration of H2(g) at 1000oC? Homework Equations h20 h2...
  2. E

    How much quantum mechanics are in quantum chemistry?

    So I am a chemistry major, but really like math and physics as well. I was wondering how necessary it would be to take quantum physics after taking two semesters of physical chemistry. I go to a small school and there aren't a host of physics classes, so quantum physics is the end of its road...
  3. Mohamad&Issa

    Elephant toothpaste chemistry project

    Hello... I'm making elephant toothpaste for my chemistry project, where I'm using activated yeast+73 ml of water and soap+10 ml of hydrogen peroxide.But the reaction is very slow.What maybe the problem or if there any catalyst please help. NOTE:after my search on internet I found that I should...
  4. F

    Selective Precipitation Chemistry Problem

    Homework Statement A solution of AgNO_{3} is added to a solution containing 0.100 M Cl^{-} and 0.100 CrO_{4}^{2-}. What will be the concentration of the less soluble compund when the more soluble one begins to precipitate?Homework Equations Ksp AgCl = 1.82 x 10^{-10} Ksp Ag2CrO4 = 1.2 x...
  5. S

    The Chemistry Mystery: Why Some Love and Others Loathe This Subject

    I can't bring myself to like this subject. And I can't do my desired course without being good at it. Its like one information after the other and some things make no sense and too many exceptions. :cry: If there's someone out there who likes chemistry, then please tell me what about this...
  6. T

    Organic chemistry, naming cycloalkenes

    Homework Statement Homework Equations The Attempt at a Solution Shouldnt the name for that be 3-fluoro-2-methyl cyclopentene instead of 4-fluoro-3-methyl cyclopentene ?, if not can someone explain to me why ?
  7. G

    How Do Significant Figures Affect Calculations in Chemistry?

    Hello I have 5.8 moles of KOH. 1Mole of KOH= 56.11g So: 5.8moles of KOH x 56.11g/1mole= 325.438g of KOH If, I want to follow the significant figures rules, what is the answer? Is it 330g? If yes, it seems inaccurate.
  8. A

    Why Doesn't Adding Water Change the pH of Acid During Titration?

    Homework Statement Ok, so, I've been thinking about this for a while now. When I was doing titration back in high school, we had to put water (so that the solution would have a larger volume to work with) in the acid in which we were going to pour base from a buret. Now, my question is...
  9. N

    Programs What could i do with a double major of physics and chemistry?

    I'm thinking of double majoring in physics and chemistry but I don't know what I can do career-wise with that double major. What kind of careers would be out there for me if I double majored in physics and chemistry, and how advanced of a degree in both would I need?
  10. T

    Confirmation of some chemistry terms.

    What is the difference between: Atomic mass Relative atomic mass Atomic weight Relative atomic weight People misuse these so many times that I've confused myself. Somebody please confirm their definitions please, thanks.
  11. C

    Solve Chemistry Problem: 3 NaOH Samples Found at Crime Scene

    I will ask the teacher personally for further explanation (he was absent), but I would like to complete the homework prior to doing so, so I can get an idea of how to resolve this problem. 3 sample of NaOH are found at the scene of a crime. The sample used to kill the Canadian goose had a...
  12. W

    Analytical Chemistry: Calculate the pH.

    Homework Statement Calculate the pH of 5.0 x 10^-8 M HCLO4. What fraction of the total H+ in this solution is derived from dissociation of water? Homework Equations The Attempt at a Solution The only thing I know to do is take -log(5.0 x 10^-8) .
  13. N

    Chemistry Interested in Physics and Chemistry

    I have big interests in both physics and chemistry and I have separate ideas of research I can do some that involve physics with no chemistry and some that involve chemistry with no physics and some that use both sciences. Can I find a career where I can study chemistry and physics sometimes...
  14. C

    Chemistry Should I bother with a chemistry career?

    Hello, PF! I'm a second year undergrad student at one of UK's leading universities (arguably one of the best in the world). Until now I've done really well in chemistry and enjoyed every second of it (I got medals at International Olympiads in high school, good grades first year at uni)...
  15. J

    Programs Is a Chemistry Minor Necessary for a Physics Major?

    Hello, everyone. I've had many of my questions answered by these forums before but this one was a little specific so I decided to make an account here. I am a third year physics major with a chemistry minor. I enjoy chemistry and feel that it can help me down the road. As far as my university...
  16. S

    Find the general solution in chemistry?

    Find the general solution of y"'-y"-y'+y=2e-t+3. Here's the work: r3-r2-r+1=r2(r-1)-(r-1)=(r-1)(r2-1)=(r2-1)2(r+1) r=1, -1 y=c1et+c2tet+c3e-t The answer in the textbook is y=c1et+c2tet+c3e-t+(1/2)te-t+3 but I don't know how to get the last 2 terms. Help me...
  17. D

    Why is it hard to love chemistry while juggling other challenging courses?

    Hi everyone I really like all of science but my two favorite sciences so far are physics and biology. I've always thought it odd that I like these two sciences but don't like chemistry as much. When I was first taking chemistry I found it boring, especially organic chemistry. But after a few...
  18. N

    Engineering Interested in Physics, Chemistry and Engineering, what do I do now?

    I have big interests in physics, chemistry and engineering as a whole and I hope that one day I can mesh these subjects together. Is there any job out there that can apply all of these subjects together into one career?
  19. N

    Programs Dual Major in Physics and Chemistry?

    Right now I'm going into my junior year of high school, and college has been on my mind a lot. I just finished AP Chemistry and I'm going to be taking AP Physics B next year and I am interested in both sciences very much, I was wondering if some colleges offer a double major program for...
  20. B

    Chemistry Electrode potentials question

    Am I right to think that the potential established at an electrode immediately when placed in solution is given by E = E° - R \cdot T \cdot log_e(Q_{surface}) where the potential E of the electrode results from the standard electrode potential (E°) of the reaction and the reaction quotient...
  21. F

    Help chemistry name for NA2CR2O7

    iupac name for NA2CR2O7 AS Iron(II) oxide
  22. T

    Chemistry BS, Looking to go into computational chemistry

    Hi Physics forum. I am a BS in biochemistry, looking into going into computer programming with my chemistry degree. I got A's in Gen Chem I and II, Organic Chem, Analytical Chem, Physical Chem, but I sucked at Biochemistry and got a C-. I got a B in Calc II but I was good at the Integration...
  23. B

    What Are the Applications of Quantum Mechanics in Chemistry?

    (Let's assume for the sake of this discussion that computational power were not an issue.) What are the applications to chemistry of quantum mechanics? So far I have only seen the Schrodinger equation being solved for a system with a hydrogen nucleus and 1 electron. Is it possible in theory...
  24. R

    Learning about gas-related chemistry.

    Hi everyone. Does anyone here know where I can start or some good introductory texts on gas-based chemistry? Any good books or chemists? Thanks all.
  25. L

    Dear Physics Forum: Calculus problem (Physical Chemistry)

    Homework Statement In the electrochemists technique of cyclic voltammetry, the peak current, I, is a simple function of the scan rate, v, according to the Randles-Sevcik equation: Homework Equations I = 0.4463nFAc(nF / RT)^1/2 D^1/2 V^1/2 Where n is the number of electrons transferred, F is...
  26. P

    How to Choose Between a Physics and Chemistry Undergraduate Degree in Europe?

    I'd like to pursue an undergraduate degree in either physics or chemistry, starting this fall in Europe (where students must choose what to study before commencing studies). Both are physical sciences that study matter, albeit from different perspectives. How could I decide which one to...
  27. M

    Feynman's Approach to Chemistry: Exploring the Fundamentals

    "Feynman" of Chemistry? Does anyone know if a chemistry book exists akin to Feynman's fundamental physics books?
  28. W

    Exploring the Difficulty of Chemistry Majors - Is Chemistry Right for Me?

    I was contemplating majoring in chemistry when I go back to university. I don't want to do this physics (not that i don't like physics nor is it that i can't - just not interested in taking the classes). Thus, I would do a Bachelors of Arts instead of science to avoid the physics. I was...
  29. P

    Chemistry Relationships & Equations, Laws

    Homework Statement Does anyone know any laws equations or any other relative information between a weather balloon and scuba diving. I need to state their relationships and how the laws and equations can be used in our daily lives. Homework Equations Henry's Law, I'm not sure what else...
  30. L

    Schools Chemistry or Physics? College Course - Year 11 Australia

    Hi everyone, I've always liked both Physics and Chemistry equally, but recently I've had to choose between either Physics or Chemistry as a course in some extension program I got into. At my age (16), which would be a better option for the future? I'm a mathematical person, so at the moment...
  31. S

    Competition between chemistry and physics?

    So...I've been set on majoring in physics for a long time, but today my chemistry teacher asked me what my major was going to be. I told her physics. So she's says "Why do you want to study physics!?" Did she say this because she teaches chemistry or what? At the beginning of the semester she...
  32. tsuwal

    Chemistry: Polar or non-polar? Dipolar moment?

    Homework Statement Is this molecule polar or non polar? What is its dipolar moment? Homework Equations The Attempt at a Solution The molecule has triple symmetry so its dipolar moment is 0. But I think it is polar because the oxygens atract the eletrons much more strongly...
  33. tsuwal

    Chemistry: Acetaminophen (paracetamol) > Phenacetin

    Homework Statement To convert acetaminophen to phenacetin it was added NaOH in ethanol and then Ethyl iodide. (Nucleophilic substitution). What would be the change in reaction velocity if insted of Ethyl iodide it was added 2-iodopropane (Isopropyl iodide) Homework Equations...
  34. R

    Quantum Chemistry: approximations using trial functions

    Homework Statement For a 3-D, spherically symmetric, isotropic harmonic oscillator, use a trial function e^αr^2 as a variational parameter. The Hamiltonian as given by the book is attached, as are two files showing screenshots of my attempt at the solution in Mathcad. I've tried it two...
  35. djh101

    Irreversible Adiabatic Expansion (Physical Chemistry)

    Homework Statement Consider the adiabatic expansion of .553mol of an ideal monatomic gas with CV,m = 3R/2. The initial state is described by P = 6.25bar and T = 306K. Calculate the final temperature if the same gas undergoes an adiabatic expansion against an external pressure of P = 1.25bar to...
  36. trollcast

    Chemistry Jobs / Employability with Chemistry / Physics degree?

    I'm just wondering about the above 2 degrees (or possibly physics and something like applied mathematics or computer science as a double honours) and what sort of outlook there is for jobs and variety of jobs out there. I'm interested in the areas of science that are working to produce new...
  37. A

    Why are enantiomers commonly used in organic chemistry and biochemistry?

    Hi everybody, I have a physics homework for Monday, and I don't understand a question very well : "Why are enantiomers very commonly met in organic chemistry and biochemistry but not so often in other parts of chemistry ?" I think I can answer the first part of the question without too...
  38. P

    Learning physical chemistry online? My professor is bad

    We are learning about NMR and ESR right now. I know physical chemistry is a difficult topic to learn because there is a lot of background information that you have to be aware of in order to understand things. My professor does not reference these background topics, speaks with a strong...
  39. W

    Programs Chemistry major looking for a way out.

    Hi everyone, I have almost finished my BS (chemistry), and I would like some advice on where to go from here. I have an interview at a med school coming up, but I'm not really sure if medicine is what I want to do right now. My undergraduate is from a mediocre university, but I have good...
  40. Z

    Help a Physics grad read up on Chemistry

    Hi all, I am a grad student with a Physics BSc. For various reasons, I have never actually done a basic pure chemistry course, even at high school level. Naturally, I have come across many concepts from chemistry in my courses, but I lack the fundamental overview of the field, and I am very...
  41. B

    How Much Limestone is Needed to React with 100 kg of Clay to Produce Cement?

    Homework Statement 1) If limestone (calcium carbonate) and clay (assume aluminum silicate) are mixed together and heated then the result is cement. Cement is a mixture of calcium oxide, carbon dioxide, aluminum oxide, and calcium silicate. These bags can be purchased at any building supplies...
  42. H

    Do I need to know chemistry to know particle physics?

    Do I need to know chemistry good to be able to learn about particle physics?
  43. M

    Organic chemistry addition reaction

    Homework Statement Number 8 is the one I was unsure of in my exam. I know a hydride shift would give it a better carbocation, however it was not tetra hedral, so I panicked, and quickly did a alkyl shift, it worked out on the exam, but I was on the verge of running out of time so I...
  44. T

    ChemE major who hates Organic Chemistry

    I am a ChemE major, and I am currently in Organic Chemistry 2. I got through OC1 by the skin of my teeth, and I currently am sitting on a 60% in OC2. Do I need to re-evaluate my major? Do you guys have any tips on how to learn this stuff? I am acing all of the homework assignments, but when...
  45. sankalpmittal

    Can anyone recommend any chemistry forums?

    Hello there, I am a high school student, and chemistry is bashing my brain hard. I am not saying that I do not understand it. I mean that when I have a doubt, where can I ask ? I know PF has a chemistry section, but I prefer maths and physics here. (No offence please). Also I have some to many...
  46. djh101

    Physical Chemistry Electives: ODE, Mechanics, or Mathematical Methods?

    Hello, everyone. I am currently a junior [physical] chemistry major and am picking out my future upper division electives. I've narrowed them down to a handful of classes and what I'm looking for is just a little background information on them, which ones might be better than others, general...
  47. C

    What Is the Molecular Formula of an Unknown Compound from Combustion Data?

    Burning a 3.230 g sample of the unknown compound in an excess of oxygen produces 4.7341 g of CO2 (carbon dioxide). The carbon initially in the unknown compound is completely converted to carbon in the CO2. If it is determined that the molecular weight of the unknown compound is 180.16 g/mol...
  48. tsuwal

    Where can I find organic chemistry exercises with solutions?

    I'm learning how to do ressonance hybrids and would like to practice. Thanks for your help!
  49. B

    Metals and Coordination Chemistry

    My syllabus notes the following points about transition metals and complex ions, but provides no textbook. d – and f – Block Elements Transition Elements General introduction, electronic configuration, occurrence and characteristics, general trends in properties of the first row...
  50. T

    Programs Finish an Associates in Chemistry Degree?

    Hi everyone. Just to let you know ahead of time this story might jump back and forth but I'll try my best to keep my thoughts straight. I'm about to graduate with BS degrees in physics and math. I applied to some graduate programs but I don't think I'll get into any because my grades were...
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