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. C

    Electrolysis (Chemistry) with electrochemical cell

    How does concentration of solution (So42) affect the voltage in a electro-chemical cell?
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    Dienophile and diene help? organic chemistry

    dienophile and diene help?? organic chemistry We never really covered how to do diels alder reactions and I am having trouble how to do these. Here is a photo of the lab page with the questions. I just need help with 2a-e and 3b-3d. Thanks.
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    Chemistry Major, want to go into Physics now

    So I am almost done with my Chemistry Major, but I really enjoy physics! Is it possible to still go into physics, maybe Chemical Physics, Astrochemistry, or Material Science. I don't want to start over, but can I still go into graduate school in Physics?
  4. M

    Chemistry Problem involving specific heat capacity and energy change

    Homework Statement A cube of gold is heated to a temperature of 94.2 degrees celsius, and then submerged in 31.3 mL of water at an initial temperature of 28.7 degrees celsius. If the final temperature of the water is 45.6 degrees celsius, calculate the volume of the cube of gold (s=0.130...
  5. M

    A book of general chemistry problems?

    Our chemistry book is a good textbook. It explains things well and in depth. The problem I have with it, however, is the exercise problems. Enough of the answers in the back of the book are wrong that it causes confusion with the proper way to solve certain problems (professor agrees and has...
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    Preparation for Chemistry Olympiad

    Hello, I am a high school student looking for resources to prepare for the US National Chemistry Olympiad. I have already taken AP Chemistry (although my teacher did not cover a few topics, such as coordination compounds) and I did well in the class and on the exam. At this point, I need...
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    Chemistry Future in Chemistry: Master's or Ph.D Degree Options

    Hello. I've been reading this forum for a couple of days and noticed that it is a lot of people with Ph.D degree in different areas so I thought this was the perfect place to ask for such a thing. I am a 17 year old student and I find chemistry (Especially theoretical) very interesting. I...
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    Chemistry Which branch of science offers the most job opportunities and stability?

    Assalamu Alaykum (peace be upon u in arabic), First of all, sorry about the thread name, because once u read this thread, there is more to asking about a chemistry question. And as a new poster, i have no clue how to fix the names of the threads i post. I am a sophmore in high school...
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    How to Calculate Mass from Density and Volume?

    Calculate the number of grams of sulfuric acid in 1 gallon of battery acid if the solution has a density of 1.26 and is 38.5 sulfuric acid by mass.
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    Is there a chemistry book that you would recommend

    I am currently taking AP Chemistry in high school but I need help. The textbook we are using is the 8th edition of Chemistry by Thomson. however I find that it doesn't explain the math portions very good and is more about memorizing. I also have the Princeton review book on chemistry. Our...
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    Chemistry Question Solution Stochiometry And Determining The Concentration?

    Homework Statement What is the concentration of all ions after 600.0mL of 2.00 mol/L Barium nitrate is added to 100.0 mL of 2.50 mol/L sodium phosphate. The Attempt at a Solution I first wrote down the equation : 3Ba(No3)2 + 2Na3PO4 = Ba3(PO4)2 (solid) + 6NaNO3 I then found the moles...
  12. R

    Chemistry vs Biology vs Computing for Electrical engineering?

    I have to decide on what subjects I want to continue on for A level and was just wondering what I should pick as my last slot. I want to do Electrical Engineering at uni when I leave school. I'm really interested in either really big applications of EE like large HV plant stuff but also I'm...
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    What the Heck? Chemistry Experts Needed NOW

    Okay so I was just sitting around and thinking about Hydrogen (weird I know) when I realized that a hydrogen ion is just a proton. So how do we distinguish between molecules such as Cl+ (Chlorine with extra hydrogen) and HCl?
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    Uncovering the Flaw in a Chemistry Lab Experiment

    Any ideas what the inherent flaw in this experiment is? Homework Statement In the lab (actual lab), we combined copper(II) sulfate pentahydrate with barium nitrate to form barium sulfate (precipitate). Every group got a 115% or higher yield than stoichiometry would predict. Ba(NO3)2 +...
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    Exploring the Charge-Carrying Capability of Diaphragms in Chemistry

    In basic chemistry courses you will learn that diaphragm prevents mixing of solutions between half-cells while maintaining ionic conductivity. What exactly carries charge through diaphragm if it's neither electrons, nor ions from the solution? What is the molecular mechanism behind that?
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    Eigenvalue Question (p2.14 in Quantum Chemistry and Spectroscopy)

    function: e^-(x^2/2) operator: d^2/dx^2 -x^2 The answer key says the function is an eigenfunction of the operator with an eigenvalue of -6. I can't figure out how to reach this conclusion. Also, Wolfram Alpha says d/dx(d/(dx)e^(-x^2/2)) = e^(-x^2/2) (x^2-1). Isn't this inconsistent with...
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    Organic Chemistry - Carbanion Question hybridization/valence/geometry

    Homework Statement A carbanion is a species that contains a negatively charged, trivalent carbon. (a) What is the electronic relationship between a carbanion and a trivalent nitrogen compound such as NH3? (b) How many valence electrons does the negatively charged carbon atom have? (c) What...
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    Regular chemistry electron configuration help

    Homework Statement Why do transition metals tend to form +1/+2 ions? Take electron configurations into account so that I can better understand this "easy" concept.2. The attempt at a solution I think it has to do with the s orbitals. These, I think are valence electrons that are easily lost...
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    UBC Honours Chem Student: Choose Chemistry or Physics?

    I'm currently an Honours Chem student at UBC (I'd say a fairly reputable school), but I'm slightly disenchanted with the program. I absolutely hate organic chemistry, and there's just not enough math thus far. I'm thinking of either elaborating my degree so I do a Combined Honours in Chem and...
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    General Chemistry problem with conversion factors

    One cubic mile of sea water, with a density of 1.13 g/cm3 contains how many gallons and how many tons of sea water? 1 cm3/.001 L 3.785 L/1 gal 1 kg/2.2046 lb 5280 ft3=1 mi3 1.13g/1cm3 X 2.2046 lb/1000 X 1 cm3/.001 L X 3.785/gal After this point I get a bit confused...
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    How importent is Chemistry in physics?

    I'd like to study Physics after Gymnasium (equivalent High School). How impotent is Chemistry in the different fields of physics? I still haven't decided which direction at all to do in physics, and I'm thinking what would be blocked by not doing Chemistry? I have Chemistry right not, but...
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    Organic Chemistry Nomenclature

    Homework Statement 4-isopropyl-2,5-octene or 4-isopropyl-2,5-dioctene? 2. The attempt at a solution 4-isopropyl-2,5-octene
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    Programs Do Chemistry Majors Have to Take the Same Calculus as Engineering and Math?

    Do Chemistry majors have to take the same calculus as do Engineering and Math majors? At my university (UC Davis), they do. I'm wondering if it is the same at your university or at most universities. I'm wondering because I'm considering majoring in Chemistry (switching out of Engineering), but...
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    Basic chemistry: sulphur dioxide shape?

    Basic chemistry: sulphur dioxide shape??! I realize this isn't homework, but it's so basic I'm ashamed of putting it in the chemistry section. I'm trying to self-teach here, but my textbook is awful and I'm even worse. Question: Workout the shape of SO2. Step 1: Draw lewis diagram to work out...
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    Schools Why Is AP Chemistry So Challenging for Me?

    I'm a junior in high school and among other advanced courses I am taking AP Chemistry 2 which is by far the hardest. Now I've had difficult classes before but I have a good work ethic and am able to work through them no matter how hard and come out with an A. While I still have an A in chem as...
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    Find "Inorganic Chemistry by J.D. Lee" eBook Free on the Web

    could anyone please tell me where wold i find the ebook'inorganic chemistry by J.D. Lee' for free on the web.please suggest me a valid link.
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    How much chemistry demanding particle physics is?

    As title says, how much chemistry would I need at the beginning of university level particle physics? If I decided to study it, would the fact that I don't have chemistry in my A levels could be a problem?
  28. M

    Chemistry - measuring the ammount of oxygen i need to to make MgO

    i have done the maths based on an online conversion calculator that said 1 liter of air is equal to 0.001m^3 in volume. my chemistry teacher tells me that my maths is wrong but won't tell me how... here is what i wrote: Failing the above, a larger crucible would hold more oxygen and the...
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    Physics and/or chemistry science book for a high school student

    I want to improve my scientific language and broaden my vocabulary, what will for sure help me in writing my physics and chemistry essays. Can You recommend me any book, which kind I mentioned in the topic?
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    Programs Can a Chemistry BS Graduate Successfully Transition to a Physics PhD?

    Hello all, I am rather new to these forums, and I have a question about lateral transfer between chemistry and physics. First, my background pertaining to physics: MATH: 3 semesters calculus 1 semester each: ordinary differential equations, linear algebra, abstract algebra, probability...
  31. D

    Citric acid effect on body chemistry pH

    I see a lot of quacky sites about acid/alkaline body chemistry claiming that lemon juice and orange juice make the body alkaline. They both contain citric acid, orange juice also has lots of potassium... I cannot think of any mechanism whereby citric acid would somehow cause a persons body to...
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    Chemistry Calorimetry Question Find Final Temp.

    Homework Statement 10.11g of CaO (molar mass = 56.08 g / mol) is dropped into a styrofoam coffee cup containing 157.0 g of H2O at 25.0ºC. If the following reaction occurs, calculate the final temperature of the water assuming that the cup acts as a perfect insulator. (Assume that the...
  33. J

    Colligative Properties, Freezing Point Depression - Chemistry Lab

    Colligative Properties, Freezing Point Depression -- Chemistry Lab Homework Statement In an attempt to hurry the experiment along a student did not completely dissolve the unknown nonelectrolyte. Will the freezing point depression of the solution be larger, unaffected, or smaller compared to...
  34. S

    Significant numbers used in chemistry confusion

    I was reading in my chemistry book about significant numbers. Also about measured and exact numbers. From what I understand, a measured quantity can be different than an exact number. The book said when comparing something, like 1 lb = 16 oz, it is an exact number because the two are the same...
  35. R

    How Many 200 mg Tablets Are Needed for a 2% Solution in a 3 oz Bottle?

    Hello, I need your help on a calculation... I have 200 milligram dissolvable tablets, and a 3 ounce dropper bottle of water. How many tablets would I need to add to the water to make a 2% solution? The chemistry/math is a bit confusing to me because the tables are measured in mass (i.e...
  36. sankalpmittal

    Courses Coaching courses in physics, chemistry and mathematics ?

    Hello PF members , I am in class 10th presently in India. I want to be selected in engineering entrance examinations. In India best are IITs ( Indian Institute of Technology) Now there are certain coaching classes in India which prepare us for engineering entrance exams and consists of...
  37. Y

    Organic Chemistry Synthesis/Mechanism

    Homework Statement Problems: http://imgur.com/qN7Iq Homework Equations n/a The Attempt at a Solution For the synthesis, I tried opening the epoxide with HBr and then adding OMe- in HOMe to substitute the Br with the OMe group in the product. However, I am unsure how to substitute the...
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    Schools Is Studying for the GRE Chemistry Exam Worth It?

    Hi everyone, I am currently a Junior Chemistry Undergraduate at UofA. I already made my decision that I want to apply for chemistry graduate school after I graduate from my undergraduate study. Based on several good discussions with other graduate students at my school, they all told me to take...
  39. T

    Need guidance with Chemistry - energy related

    Hey guys, I'm really lost on this question...could somebody please point me in the right direction? Thanks!
  40. AGNuke

    Practical Organic Chemistry - Confirm positive test

    I don't know where to ask this question, but anyways, since it was asked in an exam, so finding out the correct answer afterwards is a moral responsibility as a homework. So here I am. My question is whether the compound 2-Hydroxy-5-nitrobenzaldehyde (Did I named correctly?) gives positive...
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    Should I stick with chemistry?

    I've been reading a lot over the internet that chemistry is a dead end career, and that it will be very hard to find a job with a chemistry degree. My dad on the other hand says that I should be able to find a great job as a chemist because there is a need for scientists in the US (He is an...
  42. S

    Calculating HCl Concentration in Dilution Problem

    Homework Statement How much 2M HCl do you have to add to 5 liters of 6 M HCl, to obtain a 3.5 M HCl solution? The Attempt at a Solution I initially thought of something like m1v1=m2v2, but that doesn't seem to really work in this case :/?
  43. N

    Physical Chemistry: Estimating ΔG of an Ideal Gas

    Homework Statement Estimate ΔG for the process where one mol of ideal gas is subjected to an increase in pressure from 1.00 atm to 11.0 atm at 25.0°C. Homework Equations ΔG=ΔH-TΔS ΔH=C(p,m)(Tf-Ti The Attempt at a Solution Seems straight forward, but it seems i am not given...
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