What is Chem: Definition and 424 Discussions

Global Bio-Chem Technology Group (Chinese: 大成生化集團控股), also known as simply Global Bio-Chem, is a Chinese biotechnology company based in Hong Kong. The company is owned by Changchun Dacheng Industry Group.

View More On Wikipedia.org
  1. Q

    Thoughts on Excerpt from My Chem Prof's Textbook?

    What are your thoughts on this excerpt from my chem prof's textbook? I have a few problems with the beginning of the text and a huge problem with the bolded statement. I understand the intentions of my teacher - structure - is highly important in chemistry. Not so much emphasized in general...
  2. Ritzycat

    How can I determine the order of N in this rate law lab?

    Homework Statement Hello. I need help with a lab today that involves rate laws. The goal of this lab is to show the concentration of the reactant ions in this equation 5(HSO3) + 2(IO3) -> I2 + 5(SO4) + H2O + 3H. We did several trials of varying amounts of the ions and calculated the...
  3. A

    Help with 2 gen chem questions please

    Hello everyone, first time poster here. I'm hoping someone can help me with these two questions, they're part of a study guide for my upcoming chem 1 exam. Mythical element Z has an avg atomic mass of 107.9 u and is known to have only two naturally occurring isotopes. If 48.16% of Z exists...
  4. B

    Chem undergrad realizes interests lie in physics; do I have any hope?

    TLDR; obviously it'll be helpful if you read the whole text, but I appreciate the wall of text may put you off, so I've summarized each paragraph: Third year chemistry undergraduate at Oxford whose interests lie in physics instead. Chemistry course has a significant physical leaning, especially...
  5. P

    Stoichiometry: Calculating Reactant Mass from Product Mass

    I just wrote a test and will try to remember the question and how I answered it to the best of my ability.It was basically asking the find the mass of reactants from the mass of one of the products formed. My first step was calculate the moles of the product with known mass. Once I had the...
  6. S

    Solve Reversible Expansion of Ideal Gas: q, Work, ΔU

    Homework Statement The problem provides two paths. P1,V1,T1------->P1,V2,T3 (this is the only one i do not understand) for AN IDEAL GAS reversible expansion Pressure---constant Volume---not constant Temperature---not constant Calculate the q(rev)=? work(rev)=? and ΔU=? Homework...
  7. S

    Phys Chem Heating water with electric current

    Homework Statement 86.9g of liquid water at 304K is heated by 1.75A passing through 24.7Ω for 104s what is the final temp Homework Equations its been a while since i did physics so bear with me if i get something mixed up here q=mCs,pΔT q=ItΔψ ψ=pot dif so isn't that just V from...
  8. M

    Calc 2, Linear Algbera, PHY 1, Design class and Gen Chem 2, bad idea?

    University physics with lab general chemistry 2 with lab Design class linear Algebra Culculs 2. Does this look like an overload? At times it feels like it is and at times it feels like it can be done. the mechanics course and the general chemistry course both come with labs which is the...
  9. M

    Is the Inverse Square Law Really a Law or a Theory?

    One way to tell a law and a theory apart is to ask if the description gives you a means to explain 'why'. Well Newton's 1st Law doesn't satisfy why but how about the inverse sq law? Can't you logically deduce that? If so, that's satisfying why So according to the italicized, the inverse...
  10. Z

    Chemistry & Mechanics: Arm Expansion on Command

    Like a stretchable antenna structure, i have an arm in my project and i want that arm to expand on command so i was thing what can be done for it ... I want to use chemistry this time so i was thinking following steps: if we chose an exothermic chemical reaction that can produce CO2 having...
  11. F

    Is Chem Eng PhD worth it for me, or just Master's?

    My main reasons to want to do it would be - because I love to study (both solving problems and doing research) - to feel like I have made a contribution to the field - Also, the title of a PhD is attractive and earns respect; it's like having a huge intellectual penis. - I'm not really in...
  12. M

    Can Chem E students incorporate programming into their studies?

    Here is my schedule for the fall. Chem 1 Cal 1 intro to engineering design. I need a fourth class that isn't Mechanics/physics 1. Any ideas?
  13. D

    Add Br2/HV to (S)-1,2-Dibromobutane: Optically Inactive Product

    If we add br2 / hv to (s)-1,2-dibromobutane. Where would the radical bromine go? The book hints that the product is an optically inactive substance. So I'm guessing that the bromine would go towards the carbon that has the bromine atom on it making 1,2,2-tribromobutane? Would appreciate...
  14. M

    Graduate Chem. Es, come in please

    What were your experiences in Chem E schools? Sorry if this thread has already been made. I am first year Chem E and I was wondering if I could get some insights from graduate engineers on the website. The way the schedule is designed in Arizona is that the first two years is almost entirely...
  15. M

    Calc I, Physics I and Chem I; All in the same semester?

    Keep in mind that I have never been exposed to any physics or Cal before. However, I've enough knowledge about the chemistry. The physics and the Chemistry both come with labs. Is this too rigorous of a schedule? I've been advised to hold of the physics until I've taken the cal1 first but...
  16. T

    Chem Eng rate of heat transfer qts

    Heat Transfer Qts Engine oil at 60 oC flows over flat plate whose temperature is at 20 oC with a velocity of 2 m s-1. The length of the plate is 5m. What is the film temperature and the rate of heat transfer per unit width of the entire plate? Additional information (at the film temperature)...
  17. A

    Chem. E vs Mat. E: Choosing a Graduate Program

    I am currently having to make choices on a graduate program, and I am having a tough time deciding between chemical and material engineering. Both seem to offer highly competitive salaries and employment opportunities, but it seems to me that working as a chemical engineer would mainly be a job...
  18. N

    Intro chem help Visible light spectrum? and energy of photon? help

    on a visible spectrum scale what are the numbers for the colors of ROYGBIV? for example is violet 400-500nm and red is 700-800nm? how about the other colors? If the energy of a photon is 2.63 x 10^-19 J, how can we tell what color this is? i was looking at this electromagnetic spectrum and it...
  19. S

    What is the Percent Oxalic Acid Dihydrate in an Unknown Sample?

    Homework Statement You are given an impure sample of oxalic acid dihydrate (MW=126.068 g/mole) and asked to determine the percent of oxalic acid dihydrate present in the sample. You place 0.110 grams of the unknown sample in an Erlenmeyer flask and dissolve it in distilled water. Titration with...
  20. S

    Good online lectures/material for Gen Chem?

    Hi, my Prof. for general chemistry isn't too great, as he often goes on tangents and doesn't explain the required material. The textbook assigned (mcquarrie) is also really bad, so I've been instead reading Brown-Lemay Chemistry, which is better. Unfortunately, it doesn't cover the material...
  21. C

    [P CHem] HCL/DCL r and p branch J value assignment

    Homework Statement Assign J values for P and R branches of H35cl, H37cl, d35cl, and d37cl compounds. Homework Equations The Attempt at a Solution I have a fundamental IR spectra I did on and HCL/DCL compound. I'm extremely confused how to assign J values. I've been looking online...
  22. S

    Solving Chemistry Equations: A Guide for Homework

    Homework Statement 1.It takes 15 drops of solution A to react completely with 29 drops of solution B? Which equation below represents this reaction in the smallest whole number ratio? Assume that solution A and solution B have the same molarity. Remember that there is always a slight amount...
  23. Ascendant78

    Courses Is this normal for Chem I and Chem II courses?

    I just finished Chemistry I last semester and am taking Chemistry II this semester. These are the "101" type prerequisite Chemistry courses required for the AA. Although I earned a 98 in Chem I (with a class average of 75), I still feel like I didn't learn much. To sum it up, here are the...
  24. Mandelbroth

    [Chem] Reaction Rate (Differential Equations)

    I'm only in a high school class. I just made up this problem to see if I'm getting the right idea in the long run. That, and then there's the fact that differential equations are SO MUCH FUN! :biggrin: Homework Statement Molecular bromine (initial concentration: 0.49 M) and formic acid (initial...
  25. A

    [Chem] Problem finding a source for reaction rate constant

    Homework Statement I had an assignment where I needed to calculate reaction rate constants at different temperatures. I was supposed to use ab initio method (meaning I should use Spartan software), molecular partition functions and Eyring equation. The reaction was: H+HD...
  26. L

    Taking Calc 2, Physics 1 and Chem 1 in same semester?

    Hello, I am a student at a CC currently taking Calculus I and Intro to Chem (never had chem in high school). I have high A's in both. I would like to major in Mechanical Engineering. I was hoping to get some advice from people who have tried this schedule: Calculus II Physics I (Calculus...
  27. S

    Max Work from 800 ıC Brick Cooling to 25 ıC

    Homework Statement A young engineer notices in her plant that 1-kg blocks of brick are routinely removed from a 800 ıC oven and are let to cool in air at 25 ıC. Conscious about cost-cutting and efficiency, she wonders whether some work could be recovered from this process. Calculate the...
  28. M

    Want to pursue phd in chem e; 3.5 GPA

    I'm going to get a BS in chem e from a top 30 engineering school, and I really want to further my education in polymers in the SF bay area (eg. stanford or berkeley). However, I'm worried about my GPA - 3.50 (3.61 eng core), and GRE score (148V, 154Q practice test that I rushed through in 1/2...
  29. P

    AP CHem, finding concentration of H2O2 by titration

    Homework Statement I need to find the concentration of the H2O2 that we usedHomework Equations 2KMnO4 + 5H2O2 + 3H2SO4 → 2MnSO4 + 5O2 + 8 H2O + K2SO4 (not sure if correct) we got an average of 34.5 ml of titrant, for solution we were adding the titrant to being 5ml of Hydrogen peroxide, and...
  30. Y

    Physical Chemistry without Previous Chem Experience

    Is it a good idea to take P Chem without taking any chemistry at college level? My high school had a strong chemistry program (we did organic in high school) but I haven't done any Chemistry in college. I am currently taking Quantum Mech 2, and will be taking Thermal Physics and Condensed Matter...
  31. A

    Chem EDTA and Molarity Question. Need help

    [b]1. We had a titration lab where we titrated tap water with EDTA. Through our results we should be able to figure out the molarity of Ca and Mg ions. I think I'm doing this right but it seems to easy in comparison with everything else we are doing in lab and lecture so I just want to know if...
  32. G

    Study techniques for intro to Chem?

    I took AP Chemistry in high school and loved it and I made an A. I am taking an introduction to chemistry at my Uni, and we just got back the results of our first exam. I made a 63% on the exam and I am not happy with my performance. The class average was a 30% but that doesn't affect my...
  33. G

    How Does Solvent Type Affect the Activity of 2-Pentanone?

    Hey everyone, I need help with this question: Homework Statement 2-pentanone is an important industrial intermediate. When using the pure liquid as the reference state, in which solvents (examples and explanations) would you expect it to have an activity of a) less than one, b) one...
  34. T

    A few physical chem questions.

    Number 1 For the gas phase reaction, cyclopentene + I2 = cyclopentadiene + 2HI, we find that ln Kp = 7.55 - (4817K / T) (where the symbol K on the right hand side refers to the units Kelvin). What are the changes in entropy and enthalpy? Possible answers are ΔSo = 40.05 kJK-1mol-1 and...
  35. G

    Interesting Analytical Chem Problem

    Hi all, I need to solve this problem for my environmental chemistry class. It is supposed to be a "review" problem of concepts from analytical and gen. chem. but I certainly do not know how to do it. Homework Statement If you work at the wastewater treatment plant, you are exposed to...
  36. M

    Comprehensive and Concise Chemistry Resource for All Levels

    hello! I need a chemistry book or online resource or anything, that will go from the very basics (as if the reader doesn't have much math, phys, chem, background) to the most possible depth of knowledge it surely must be accurate and comprehensive but what I really want is to be consice...
  37. A

    Programs Chemistry Major: Am I on track for Physical Chem?

    So I am a Chemistry major, but am behind on my math (was a Biology major but switched because I decided I would rather minor in Biology so as to avoid the boring plant and evolution/ecology stuff, plus I love Chemistry lol) and so am only taking calculus II this coming semester. My adviser wants...
  38. B

    Physics Undergrad to P Chem Gradute/Career?

    Hi everyone, I've been doing a lot of soul searching over the past year. I am an undergrad who recently became an applied physics major, with a chem and math minor. I am probably going to turn the math minor into a double major. Anyhoo, with that brief intro, I was wondering if there was...
  39. M

    Combinatorial chem - Stills binary code tag system

    In my med chem book: http://books.google.ie/books?id=Qe9lsbfM_m0C&pg=PT170&lpg=PT170&dq=chemistry+binary+code+tag+system&source=bl&ots=ut23YiKXDW&sig=iWH860UeYHYSwBM_ESbxnLXNrQw&hl=en&sa=X&ei=7XcVUNTpCNSThgeVwoGgAQ&redir_esc=y#v=onepage&q=chemistry%20binary%20code%20tag%20system&f=false they...
  40. N

    NE B.S. vs. NE and CHEM E joint major

    Hi, I’m a transfer student to UC Berkeley (fall 12), coming from a community college. I am transferring as a nuclear engineering major, but I can choose to do a joint major program in chemical and nuclear engineering (core courses are taken from both majors). The reason I’m considering the...
  41. M

    Exploring the Capabilities of Synthetic Chemistry and Chemical Engineering

    Hello! I would like to know in brief what synthetic chemistry and chamical engindering can do, what's their capabilities in the present time. Can it create for me a molecule or material with the exact characteristics that I want? What characteristics of it, it can adjust? Thanks
  42. C

    Does an O Chem I and II Rxn Mechanism Bible exist?

    I start Organic II in the fall. I'm looking for a place that has O Chem I and II reaction mechanisms with arrow pushing shown. Yes, I'm lazy and don't want to make more note cards. I apologize if I was unable to find it with the search function.
  43. BloodyFrozen

    Preparing for AP Chem & AP Physics

    Does anyone know/have a list of topics that a HS student should know for chemistry and physics before entering into their respective APs? (Basically, I'm asking what should a HS student know for a Pre-AP leveled cumulative final exam?) Any important topics that a HS should know are welcome...
  44. marcus

    How new are carbon chem and rocky planets?

    I don't know much about this, only looked into it a bit yesterday. If you know more or can find out something, please contribute. Abraham Loeb (eminent Harvard astroph.) says, if I understand him correctly, that light from stars richer in heavy elements than the sun has been observed at...
  45. T

    Chem major who hates Organic Chemistry?

    I am chem major currently taking organic chemistry. I am ashamed of admitting I hate organic chemistry. This is not even science. It seems to me though, it is a branch of engineering. You have stuff, you make new stuff. You increase your yield and figure out steps to synthesize something. I...
  46. T

    Recommendation for Chem Lab Simulator?

    I was wondering if anyone could recommend a good simulator to play around with. I'm a chem student and have always wanted my own lab, but having one is expensive and potentially dangerous considering I am still living at home. But i would like to play around with a simulator, preferably a free...
  47. B

    Difficulties in Organic Chem. Lab

    Hi, this is my first post. I'm generally more of a blog/message board reader than a contributor, but there's really been something that has been eating away at me, making it difficult for me sleep at night. (Note: long post coming up) Last semester in Organic Chemistry I, I made a huge...
  48. R

    Ideas for work experience for Chem. Eng, E.E. or physics?

    I'm interested in studying Chemical Engineering, Electrical and Electronic Engineering (I'm more interested in Electronic) or Physics at university. I'm looking to get some work experience days for after my GCSEs. I have 4 days at the end of June for work experience (I also could get more...
  49. Z

    Schools Math Grad School, Gen Chem Grades

    Hi everybody. I'd like to go to graduate school in math or applied math. My question is how my grades in a gem chem course my factor into this. For scheduling reasons I'm in an honors sequence and looking at B's throughout since I'm not a chem major (taking the course fulfills requirements for...
  50. P

    Testing Khanacademy and Selfstudying AP Calc AB and SAT chem

    Quick Questions: Does Khan Academy chemistry playlist on Youtube cover all the SAT chemistry topics in its chemistry playist? Also, I'm planning on self studyng ap calc ab (w/o prior calculus knowledge). Will just watching the calculus playlist on that channel up to the partial derivative...
Back
Top