1,475 results, page 2
  1. math

    If cos(3 x)6Ó14 x e^2 y=0, find [ dy/dx] using implicit differentiation. In this problem, you should differentiate both sides of this equation with respect to x. First, using implicit differentiation, differentiate the left side of the equation with
  2. Chemistry

    Assuming that the smallest measurable wavelength in an experiment is 0.330 fm(femtometers), what is the maximum mass of an object traveling at 157 m·s^–1 for which the de Broglie wavelength is observable? mass = ? kg Chemistry - DrBob222, Monday,
  3. Chemistry

    Assuming that the smallest measurable wavelength in an experiment is 0.330 fm(femtometers), what is the maximum mass of an object traveling at 157 m·s^–1 for which the de Broglie wavelength is observable? mass = ? kg Chemistry - DrBob222, Monday,
  4. English

    Hello! I will type 2 exercises from the lesson I am teaching on Wednesday-english as a foreign language - 8th graders ( it will be graded) I need you to help me with some ideas. It says: LEAD- IN: A Here is a list of some natural sciences: BIOLOGY
  5. math

    Elin estimates her probability of passing French 0.6, passing chemistry is 0.8, (a)determine the probability that elin will pass French but fail chemistry (b) pass chemistry but fail French (c) pass both classes (d)fail both classes
  6. Chemistry(Please respond)

    Calculate the pH of an aqueous solution of 0.15 M potassium carbonate. I know that pH = -log(H30+) but I am not sure how to start this problem. Chemistry(Please help) - DrBob222, Saturday, April 14, 2012 at 11:09pm Hydrolyze the CO3^2-. CO3^- + HOH ==>
  7. chemistry

    Effusion/Diffusion Chemistry Help!!! If 4.83mL of an unknown gas effuses through a hole in a plate in the same time it takes 9.23mL of Argon, Ar, to effuse through the same hole under the same conditions, what is the molecular mass of the unknown gas?
  8. math

    In a class of 50 student 28,22,20 of them offer physics,chemistry and biology respectively also,4 of them offer physics and chemistry but not biology,3 offer physic and biology but not chemistry,6 offer biology and chemistry but not physics if 13 of them
  9. Advice...about chemistry degree Dr.Bob

    Based on the question topic posted by Britney below titled:In your opinion (your answer to this reminded me of something) (I posted the same thing there but I thought it was improper to piggyback on that post so I posted this under a new topic) I don't

    1.Chemistry Question: A 0.1 M solution of acetic acid is titrated with 0.05M solution of NaOH. What is the pH when 60% of the acid has been neutralized? The equilibrium constant (Ka) for acetic acid is 1.8x10^-5 2. Chemistry question: On average, how far
  11. chemistry

    Hi, Does anybody know any good websites that can teach me step-by-step basic chemistry (through power points) to AP chemistry? I would greatly appreciate it! Since this is not my area of expertise, I searched Google under the key words "AP chemistry
  12. planning

    Ms. Sue, you told me last time to search up my college to see what courses are required for hygienist, and so this is what I got. 2. The course choices that I make today lead to the fulfillment of this dream by them providing all the knowledge that I need
  13. Math

    First student bought art, math and history books for $72. a+m+h=72 Second student bought art, chemistry and history books for $80. a+c+h=80 Third student bought chemistry, math and history books for $61. c+m+h=61 Fourth student bought art, math and
  14. Chemistry

    I need to calculate the molecular mass of ehtylene glycol based on the freezing point depression. The teacher said that for glycol i=1 and to use the equation m=delta T / Kf X i Kf = -1.86C/m so I did -2.5C / -1.86 X 1 = 1.344 I know that 1.344 can't be
  15. statistics

    Leslie took two midterm exams and earned the following scores: 82 on the chemistry exam (class distribution: μ = 75, σ = 6.25) and 63 on the physics exam (class distribution: μ = 59, σ = 3.57). Rounding to two decimal points, on which exam should
  16. Chemistry

    I posted a question like this but my numbers were actually wrong. These are the correct ones. 5.94e-3 / 1.11e-3 = 5.33e-2/2.66e-2 5.35 = 2.00^m I guess this is not correct because I do not know a whole number that will give you 5.35. Chemistry - DrBob222,
  17. math

    Emily surmises that the probability that she will pass math or chemistry is .95, the probability of her passing math is .7, and the probability of passing both is .55. Find her estimate of the probability of passing chemistry?
  18. math

    A textbook store sold a combined total of 462 biology and chemistry textbooks in a week. The number of biology textbooks sold was two times the number of chemistry textbooks sold. How many textbooks of each type were sold?
  19. math

    A textbook store sold a combined total of 315 physics and chemistry textbooks in a week. The number of physics textbooks sold was two times the number of chemistry textbooks sold. How many textbooks of each type were sold?
  20. Chemistry - Science (Dr. Bob222)

    Posted by Ana on Saturday, May 3, 2014 at 11:23am. A zinc-copper battery is constructed as follows (standard reduction potentials given below): Zn | Zn2+ (0.10 M) || Cu2+ (2.50 M) | Cu Zn2+ + 2 e- → Zn(s) Eº = -0.76 V Cu2+ + 2 e- → Cu(s) Eº = 0.34 V
  21. Chemistry

    Which aqueous solution below is expected to have the lowest freezing point? Assume 100% dissociation for ionic species. 1)0.25m MgBr2 2)0.30m Na2SO4 3) 0.50m KCl 4) 1.0m sucrose 5) 0.40m Cr(NO3)3 I think that the answer is 0.30NaSO4 but I am not positive.
  22. Science

    How does the silly putty made up of glue gel differ from the silly putty made of soap in terms of texture ? How would the touch be different and why? Chemical structure? .....? Science:Chemistry - bobpursley, Friday, February 21, 2014 at 9:53pm Have you
  23. Chemistry

    Hi you guys please help me with my chemistry homework, i need to find all these items and take them to my class in a ziploc bag *a hydrocarbon with a molecular mass greater than 100g/mol *2 porpanol *an aromatic compound(not the common usage of "aromatic"
  24. math

    In a class of 80 students,53 study Art,60 study biology,36 study art and biology,34 study art and chemistry,6 study biology and 18 study biology but not chemistry.Determine the number of students who study =Art only =Chemistry only
  25. physics

    doing webwork when i came across this question. sure i had it right but apparently im not. The weightless horizontal bar in the figure below is in equilibrium. Scale B reads 4.20 kg (N.B. as you know, the scale should read N, but no one told the
  26. DrBob222

    I know I posted this but you didn't answer! Please help!!!! Consider the following reaction at 298 K: C(graphite) +2Cl2 (g) -----> CCl4(l) Calculate the following quantities. Delta H: -139 kJ/mol deltaS(sys)=? J/mol*K deltaS(surr)=? J/mol*K deltaS(univ)=?
  27. Chemistry

    Can someone please help me on this two Chemistry questions...they are from my lab....the lab was on Acids and Bases using Red Cabbage Indicator. Q1- How consistent was the cabbage juice indicator for this lab? Discuss the limitations of using red cabbage
  28. chemistry

    I am enrolled in analytical chemistry after a 4 year break from any chemistry. I was recently given a problem set and I need some help on the following: A 0.899g sample containing epsom salt, MgSO4 & 7 H2O, and other non-hydrated materials was dehydrated
  29. MATHS

    in a class of 60 students,the number of students who pass biology is 6 more than the number who pass chemistry.every student passed at least one of the two many pass in only many pass in only chemistry.
  30. Majoooooor Help please please help me

    Please can you give me what are the products , the colour of the flame, how does it react when : 1- Zinc reacting with oxygen Zinc reacting with air 2- Iron filings with oxygen Iron filings with air 3- Copper reacting with oxygen Copper reacting with air
  31. chemistry

    I'm sorry, but this is a re-post. I couldn't find the original post;-( so, does anyone have any suggestions for helping a student make a passing grade in college chemistry? She took it twice and didn't pass. Any suggestions would be appreciated. I thought
  32. chemistry

    how many grams of sodium carbonate are needed to prepare 0.250 L of an 0.100 M aqueous solution of sodium ions? well normally you go moles=grams/molar mass than M= moles/L but when looking for grams? what do you do........multiple .250 by .100 than divide
  33. Chem

    if the pressure was increased in this reaction : 2NO(g)+ O2 =====> 2NO2
  34. Chemistry

    Fluorine reacts with oxygen to yield oxygen difluoride. 2 F2(g) + O2(g) 2 OF2(g) What is the value of K if the following concentrations are found at equilibrium: [O2]= 0.200 mol/L, [F2]=0.0100 mol/L, and [OF2]=0.0633 mol/L Chemistry - DrBob222, Thursday,

    Mr. Pennymarch, the advertising manager for Chemistry Today magazine, is responsible for selling advertising space in the magazine. The magazine deals primarily with chemical processing technology and is distributed solely by subscription. Major
  36. science

    What are 3 chemical properties of iron and 2 chemical properties of sodium? Thanks. That helped a little.
  37. chemistry

    Using this data, 2 NO(g) + Cl2(g) == 2 NOCl(g) Kc = 3.20 X 10-3 NO2(g) == NO(g) + ½ O2(g) Kc = 3.93 calculate a value for Kc for the reaction, NOCl (g) + ½ O2 (g) == NO2 (g) + ½ Cl2 (g) A. 20.2 B. 2.06 X 10-4 C. 4.49 D. 4.84 X 10-3 E. 0.223 eliminated
  38. chemistry

    Using this data, 2 NO(g) + Cl2(g) == 2 NOCl(g) Kc = 3.20 X 10-3 NO2(g) == NO(g) + ½ O2(g) Kc = 3.93 calculate a value for Kc for the reaction, NOCl (g) + ½ O2 (g) == NO2 (g) + ½ Cl2 (g) A. 20.2 B. 2.06 X 10-4 C. 4.49 D. 4.84 X 10-3 E. 0.223 eliminated
  39. Chemistry

    Hi! I'm in chem class and I don't know the answer to these questions I have several metal alloys and have to tell their general elements that make them up for example bronze - copper and tin What is the elements that make up Pewter? Also I was woundering
  40. Chemistry

    Find the value of delta H net for the following equation: SnBr2(s) + TiCl4(l) -> TiBr2(s) + SnCl4(l) I know that I already posted this once but I am still lost on what to do. I know that TiCl4=-804.2 and SnCl4=-511.3 but I thought that the values for SnBr2
  41. algebra

    in a class of 30 students , there are 22 students who study chemistry but not physics, 4 who study physics but not chemistry and who study neighter chemistry nor physics. how many students in the class study physics
  42. Chemistry

    If you add 0.35grams NaF to 150mL of a 0.30M HF, what is the pH of the resulting solution? To start off would I use the value of 1.4e-11 for F^-^ and 7.2e-4 for HF? Chemistry(Please help) - DrBob222, Tuesday, April 10, 2012 at 12:04am This is a buffer
  43. Chemistry

    1. Imagine that you work at a company that prepares chemical solutions. You are asked to label a solution to sell to different customers. One customer is a hospital, another is a chemistry lab at a university, and a third is a physics lab at a university.
  44. chemistry

    Carbon and silicon are both in Group 14 of the periodic table. (i) Identify compounds which illustrate similarities in the chemistry of carbon and silicon. (ii)Identify compounds which illustrate significant differences in the chemistry of carbon and
  45. Chemistry

    Convert a pressure of 23.8 in. Hg into kilopascal. Ok so I looked up kilopascal and it Said 1 Kpa = 1000 pa So I began to set it up like this 23.8 / 29.2 x1000 am I correct Chemistry - DrBob222, Thursday, October 13, 2011 at 1:48pm I don't think that will
  46. Chemistry(Please help)

    delta Go = -431.16kJ/mol - (298k X 0.12529 kJ/K*mol) I am having trouble converting the units for delta H and delta s to match. I multiplied delta H by 1000 to get kJ but this didn't give me the correct answer. Chemistry(Please help) - Dev, Wednesday,
  47. Chemistry(Please help, thank you)

    I have to calculate the concentration of I2 produced (# of moles of I2 produced / L) based on the stoichiometric ratio in the following equation. 2S2O3^2- + I2 -> 2I^- + S4O6^2- Chemistry(Urgent, please help) - DrBob222, Sunday, February 26, 2012 at 9:47pm
  48. Organic chemistry: dehydrohalogenation

    Hello. I know you guys don't do organic chemistry but because I got so much help from you guys in general chemistry, I was wondering if you guys can help me out again. :P Here's my question. In dehydrohalogenation, how do you know whether a reaction is E1
  49. Chemistry

    The energies, E, for the first few states of an unknown element are shown here in arbitrary units. n 1 E -11 n 2 E -5 n 3 E -2 n 4 E -1 n ... E ... n infinite E 0 A gaseous sample of this element is bombarded by photons of various energies (in these same
  50. 11th grade

    what exactly is chemistry?
  51. MTI

    what is chemistry
  52. chem

    need help on chemistry below
  53. science

    chemistry help
  54. chemistry

    in chemistry what is aq
  55. sammy


  57. chemistry

    Where can I find the answers to these questions in my text, "fundamentals of analytical chemistry" by skoog, west, holler and crouch. 1. Why is acetylsalicylic acid analyzed using back titration? 2. Discuss the importance of simmering the tablet in the
  58. Chemistry

    1. How could a chemistry student change NaOH(s) to NaOH(aq)? s= solid aq= aqueous 2.) How could a chemistry student change NaOH(s) to NaOH(l) s= solid l= liquid
  59. maths

    In a class of 60 students,the number of students who passed biology is 6 more than the number who passed chemistry.Every student passed at least one of the two many students passed biology many students passed chemistry many
  60. Chemistry

    Sorry, just asking a question on chemistry.
  61. chemistry

    What does a slash (/) mean in chemistry?
  62. chemistry

    why is chemistry so important
  63. chemistry

    Does Chemistry have anything to do with meteorology?
  64. chemistry

    i need help with chemistry homework
  65. Chemistry

    why is chemistry needed
  66. Chemistry

    What is another name for mole in Chemistry
  67. Science

    List all of the things that are physical property. You will find some listed here. There are very many others, but they would require a lot of effort to explain what they mean. Isn't
  68. chemistry

    Under the appropriate conditions, NO forms NO2 and N2O: 3NO(g) N2O(g) + NO2(g) Use the values for delta G naught for the following reactions to calculate the value of Kp for the above reaction at 500.0 C 2NO(g) + O2(g) 2NO(g) delta g=-69.7 kJ 2N2O(g)
  69. Chem

    A carless chemistry student pours 200 grams of methanol, a flammable substance into the sink. Another careless chemistry student causes the bad situation to get even worse by dropping a lit match into the sink. The metanol burns completely with 300 grams
  70. Biology

    Why do you you need to perform dilution(s)in chemistry?
  71. physics

    What model is the basis for chemistry?
  72. previous chemistry.

    can some one reply to my last chemistry post? thanks.
  73. Drbob222

    Can you please help me with some questions I have on my Chemistry lab?

    Someone please answer my question below in AP CHEMISTRY.
  75. unt

    chemistry ---- 77=25 to the x power. Can anyone assist.
  76. Please Help

    Can someone please help with the chemistry problems? I need them to study.
  77. PLZ look at Chemistry Questions!!!

    No chemistry questions are getting answered =(
  78. chemistry

    Abstract 4 chemistry of starch
  79. chemistry

    Chemistry Suspension Examples...
  80. chemistry

    Chemistry Suspension Examples...]
  81. science

    write aout chemistry
  82. Chemistry

    What is weighted average in chemistry?
  83. Research paper topics


  85. Chemistry

    Road map in chemistry ?
  86. chemistry

    what topics are under periodic chemistry?
  87. chemistry

    which topics are under periodic chemistry II?
  88. Chemistry

    What are the parts of a calorimeter used in chemistry?
  89. DrBob222

    I really need help on these chemistry problems. Can you please help me work them. Please?
  90. Geography

    What is the relation between geography and chemistry
  91. Chemistry

    In which direction will the net reaction proceed X(g)+Y(g)Z(g) Kp=1.00 at 300k for each of these sets of initial conditions? a) [X]=[Y]=[Z]=1.0 m net reaction goes to the left net reaction goes to the right reaction is at equilibrium I chose 3 for a. b)
  92. Chemistry

    At what initial concentration would a solution of acetic acid (ka=1.8x10^-5) be 2% ionized? Thanks Responses Chemistry - DrBob222, Thursday, February 12, 2009 at 10:00pm Let's call acetic acid HAc. Then the ionization is HAc ==> H^+ + Ac^- We will call the
  93. Chemistry

    Thank you for your help. I did want to clarify why you are only calculating the Molar Mass for H2 and not the molar mass for H2O (or even H2O2). I'm not sure why you did this. Please clarify. See below: The following reaction represents the decomposition
  94. ap chemistry

  95. AP chem

    is there anyway that i could also get help with the chemistry problem that eric posted?
  96. 11th grade

    how do you solve a dilution problem, this is chemistry
  97. chemistry

    what is chromatography? Its history,purpose in chemistry.
  98. Chemistry lab

    List 10 equipment use in the chemistry lab and their uses
  99. biology

    how does concepts of chemistry affect biology?
  100. Chemistry

    Why would a firefighter or a reporter need to understand chemistry?


  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
  6. 6
  7. 7
  8. 8
  9. 9
  10. 10
  11. 11
  12. 12
  13. 13
  14. 14
  15. 15