chemistry! URGENT

61,843 results, page 26
  1. Chemistry lab

    List 10 equipment use in the chemistry lab and their uses
  2. chemistry+reply

    can someone reply to my previous chemistry thread please?
  3. PLZ look at Chemistry Questions!!!

    No chemistry questions are getting answered =(
  4. Urgent... I need help please

    When do you think the prosecutor's office should become involved in a case (pre-arrest or post-arrest)? Do you think involvement by a prosecutor in the original stages of an investigation is a good idea? Can a defense attorney ever become involved in a
  5. Chemistry (DrBob222)

    Hi Dr. Bob would you please tell me what D rpresents? Thank you! What is the reactant, products, and what compounds is it? Is it H2O, O2, or what? What are the transition molecules? Help please. Do as below to get to the image. I couldn't put the URL in
  6. physics (Urgent)!!!!!!!!!!!!!!!!!!!!!!

    A small block of mass m=1 kg glides down (without friction) a circular track of radius R=2 m, starting from rest at height R. At the bottom of the track it hits a massless relaxed spring with spring constant k= 9 N/m, which starts to be compressed as the
  7. physics (Urgent)!!!!!!!!!!!!!!!!!!!!!!

    A pendulum of mass m= 0.9 kg and length l=1 m is hanging from the ceiling. The massless string of the pendulum is attached at point P. The bob of the pendulum is a uniform shell (very thin hollow sphere) of radius r=0.4 m, and the length l of the pendulum
  8. Note to physics, chemistry students

    Please note the spelling of Physics, and Chemistry. If you are a college student in those courses, and cant spell them, frankly, asking for help here is insulting to your college and you.
  9. Chemistry

    The primary route for making copper iodide is by reacting potassium iodide with copper sulfate: 2CuSO4 + 4KI + 2Na2S2O3 ==> 2CuI + 2K2SO4 + 2NaI + Na2S4O6 Identify potential green chemistry and green engineering challenges of the reaction.
  10. chemistry

    I'm working on substitution organic chemistry problems and I just had a question. There's an equation in which a molecule is treated with methanol in an acetone solution. Would the reaction be SN1 or SN2? I thought that it was SN2 because of the aprotic
  11. chemistry

    In the chemistry exp molar mass of a volatile liquid what will be the outcome if the hole in the aluminu foil was larger would it make the molar mass high or low. Or what will happen if yhr water vapors condensed under the aluminum foil before the final
  12. statistics.urgent please help..

    A local college cafeteria has a self-service soft ice-cream machine. The cafeteria provides bowls that can hold up to 16 ounces of ice-cream. The food service manager is interested in comparing the average amount of ice-cream dispensed by male students to
  13. probability

    urgent till 3 pm i have in colombia¡ 1 Alice has five coins in a bag: two coins are normal (i.e., fair with one face Heads and the other face Tails), two are double-headed (i.e., both sides are Heads), and the last one is double-tailed (i.e., both sides
  14. university chemistry

    this is for a chemistry laboratory experiment called "how much caffeine is there in instant coffee" What should be the pH of the aqueous layer to extract caffeine? There are three aqueous solutions that you may choose from. A. pH >14, using 2.5 M NaOH
  15. Chemistry

    My chemistry teacher said that the pCO2 value increases during hypoventilation. Why is that? If hypoventilation causes shortness of breath, would that not increase the CO2 concentration, therefore decreasing pCO2? Because if you think about pH, a larger H
  16. Chemistry

    My chemistry teacher said that the pCO2 value increases during hypoventilation. Why is that? If hypoventilation causes shortness of breath, would that not increase the CO2 concentration, therefore decreasing pCO2? Because if you think about pH, a larger H
  17. Chemistry

    My teacher gave us the answer to a chemistry problem and i cannot figure out how she got the answer. Can you help me work out this problem so i can better understand it. A gas under an initial pressure of 0.60atm is compressed at a constant temperature
  18. 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
  19. Chemistry

    When 155 mL of water at 26 degrees Celsius is mixed with 75 mL of water at 95 degrees Celsius, what is the final temperature of the mixture? (d Water = 1.00 g/mL) Im really stuck on this problem and chemistry isnt exactly my strong point, thanks in
  20. statistics urgent

    Consider all cars that are involved in an accident and assume that all cars are classified as either small or large. The probability that a small car is involved an accident is .2 if a small car is involved in an accident, the probabbility that there was
  21. Spanish #1 (URGENT)

    Can someone please check my work? Look at the words in the vocabulary list and write them in the appropriate column. Items in word bank may be used more than once. las cortinas el armario el espejo el televisor el comedor la cómoda la cama el sofá la
  22. science very urgent help?

    Susan has heard that taking an over-the-counter ‘energy’ pill, which contains as much caffeine as a strong cup of coffee, makes people feel alert and ‘speedy’. She wonders if taking this pill will make a difference to the reaction times of people
  23. Chemistry

    Can Someone describe the structure of ionic compounds for me please.. Ionic compounds consist of a three dimensional array network of + and - ions. I expect you already know that. As to structure, here is a web site that may help. Repost if you have
  24. Math

    At small town high there are 100 students,each of whom takes atleast one of Biology,Chemistry,or physics.There are 50 student in Biology,60 in chemistry,and 70 in Physics.If 24 students are enrolled in exactly two of the classes,how many students are in
  25. college: Chemistry

    Hi there I need help with my chemistry homework There are two parts to the first question and i did the first part and i got E= -6.54E-18J. Part A) Calculate the energy (in J) of the photon associated with the transition of electron in He from n=2 to n=1.
  26. Chemistry pls help

    I have a chemistry question Please advise how do I prepare 1L of 75% H2SO4 from concentrated H2SO4 (98% of density 1.84g/ml)? Do you have an equation which i can use? Someone gave me the following equation but I do not understand it. Vx1.84x0.98={(1000-V)+
  27. math urgent please

    Petr has a cylindrical block of wood od diameter 6 cm and height 18 cm. He glues the base to a board, but wants to paint the rest of the block. He wants to paint the bottom half of the wood black and the top half white. a) Calculate the surface area of the
  28. Maths

    In a class of 45 students, 24 do arts, 20 to chemistry and 22 to biology. All the students do at least one of 3 subjects.3 do all the 3 subjects while 7 do art and biology, 6 do art and chemistry but not biology. How many do biology only, chemistry only or
  29. Chemistry

    Write balanced net ionic equations for the precipitation reactions that occur when the following solutions are mixed. If no reaction occurs, write "no reaction" a) silver nitrate and lithium hydroxide b) ammonium sulfide and cobalt (II) bromide I'm
  30. Physical Chemistry Help!

    I am posting a link to the jpeg file of the physical chemistry homework i need help with, because everytime I try typing it out, I just get wierd symbols. If somebody could please help, that would be greatly appreciated! Thanks~ =) img.photobucket. com/
  31. chemistry

    What is the concentration of the Mg2 ion in solution when [CO3-2] = 0.25M given that the Ksp= 6.82 x 10-6 for the following reaction MgCO3-------->Mg +. CO32- Chemistry - DrBob222, Friday, November 11, 2011 at 5:34pm Ksp = (Mg^2+)(CO3^2-) Substitute
  32. soil chemistry

    Can someone please help me answering this question regarding soil chemistry? A sandy soil has a CEC = 5 meq/100g and a K saturation = 6%. An alfalfa crop yields 5 ton/ac/yr at 3% K. Calculate initial exchangeable K and estimate final exchangeable K. Where
  33. 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
  34. Chemistry

    3. A chemistry student makes up a 0.10 M solution of NaF(aq) and finds the pH to be 8.09. a. Explain why the presence of F- in this solution affects the pH. b. Write out the acid/base equilibrium equation for the reaction of F- with water. c. Use the
  35. organic chemistry

    a careless organic chemistry student was performing "competing nucleophiles in nucleophilic substitution reactions" experiment , and left his container of tert-butyl chloride and tert-butyl bromide open to the air for several hours. what happened to the
  36. Coordination Chemistry

    A particular metal ion octahedral complex has the same number of unpaired electrons (non-zero) whether the complex uses weak or strong field ligands. List several fourth period transition metal ions that could have this behavior. Also, if someone could
  37. 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
  38. 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
  39. Science (URGENT)

    Can someones please check my work? 1. Why does a liquid take the shape of whatever container it is in but does not expand to fill the container completely? A: It takes the shape of its contaienr because its particles can slip past each other. but it has
  40. Green Chemistry

    The primary route for making copper iodide is by reacting potassium iodide with copper sulfate: 2CuSO4 + 4KI + 2Na2S2O3 ==> 2CuI + 2K2SO4 + 2NaI + Na2S4O6 Identify potential green chemistry and green engineering challenges of the reaction.
  41. College: Chemistry

    Hi there, I need help on my homework for chemistry and I do not understand the step on how to work this problem out. Please help me with this problem: On a Sunday morning while having your breakfast you determine that you need about 2.95X10^(5)J to heat
  42. Chemistry

    can anyone help me on my chemistry problem. i need a merck index to solve this. i have a PH of 10.7 and the nearest solution that is near to it is 10.32. The solution that is 10.32 is NaHCO3. i subtract both of them to get the ratio of log (HA)/(A-). i
  43. chemistry

    Gasohol contains ethanol (C2H4OH)(l), which when burned reacts with oxygen to produce CO2(g) and H2O(g). How much heat is released when 12.5g of ethanol burns? C2H5OH(l) + 3 O2(g) --> 2 CO2(g) + 3H2O(l) Delta H = -1368kJ Chemistry - DrBob222, Wednesday,
  44. ap chemistry

    home / study / questions and answers / science / chemistry / balance the following example of a heterogeneous ... Your question has been answered! Rate it below. Let us know if you got a helpful answer. . Question Balance the following example of a
  45. Science (Chemistry)

    I'm not sure how to do a couple of problems on my chemistry worksheet. Can you please help me? You dissolve 0.00902 g of naOH in enough water to make 1000 mL. What is the Ph of this soultion. What is the molarity, pH, and pOH of 5.00 of naOH in 750.0 mL of
  46. Chemistry

    Could someone please check my Chemistry homework? The molecular formula for cisplatin, a chemotherapy agent, is PtCl2(NH3)2 (The numbers are all supposed to be subscripts) 1. What is the molar mass of cisplatin? Ans: 300.06 g/mol 2. How many moles of
  47. Chemistry

    I keep reading that lead is a poor electrical conductor, but I would like to know the chemistry of why exactly it is a poor conductor.
  48. Chemistry

    Balancing chemistry equations and need help! Thank You!? Help balancing any of the following equations: Cl2+Na Br----> NaCl2 + Br Na+LiOH---->
  49. 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
  50. Chemistry

    I'm stuck on this one problem in Chemistry: A student measures the mass of an object as 2.32 grams and its volume as 34.56mL. The student then calculates the density to be 0.067129629. There are two things wrong with the students value for density. What
  51. chemistry

    Sodium bicarbonate is often used to neutralize acids, such as the following reaction: NaHCO3 + HCl ---> NaCl + H20 + CO2. What is the normality of a sodium bicarbonate solution containing 5.08 g NaHCO3 in 150.0 mL solution? this chapter in chemistry is
  52. English

    Can you please check these sentences for me? It's really urgent. 1) At eighteen you can get married without your parents' permission. At eighten years of age/When you are eighteen ... (are they both correct?) 2) You can't get married without your parents'
  53. 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"
  54. 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
  55. Chemistry

    When someone buys fish at the fresh fish market, they should smell the fish to test for freshness, the less “fishy” the smell the fresher the fish. I am supposed to explain the source and chemistry, including reactions, structures, and names of the
  56. Chemistry

    In an organic chemistry lab, why is the organic layer usually the upper layer in the separatory funnel while the aqueous layer is usually the bottom layer?

    " An ATTEMPT to healthy living can cause misery. How true is this" Are these arguments good/fair enough ?? against : a) attempting to live a healthy lifestyle means involvement in sports and outdoor activities, yoga classes, gym bla bla bla. these help one
  58. Soxhlet extractor

    Does anyone know what kindo of chemistry lab course(Organic, Physical, etc.) might use a soxhlet extractor in the experiments? Sheryl Certainly Organic It is used in organic chemistry. The URL provided by
  59. Chemistry!! - bobpursley please

    Calculate the maximum wavelength of light capable of removing an electron for a hydrogen atom from the energy state characterized by the following when n=4 =__________nm Responses Chemistry!! - bobpursley, Wednesday, October 22, 2008 at 4:05am So the two
  60. Calculus (Urgent Help)

    Okay, I need major help! Can someone tell me if these statements are true or false ASAP please. Thank you. 1. If ƒ′(x) < 0 when x < c then ƒ(x) is decreasing when x < c. True 2. The function ƒ(x) = x^3 – 3x + 2 is increasing on the
  61. Chemistry

    What is the final concentration (M) of a solution prepared by diluting 50.0 mL of a 6.00 M KCl solution to a volume of 0.500 L? A. 1.67 B. 0.600 C. 0.0167 D. 3.0 E. none of these My initial thought was to take the 6.00 M KCl/0.500 L, for an answer of 12.
  62. bio101

    2. Find a media piece—article, video, presentation, song, or other—that recognizes the fundamental concepts of chemistry in biology. Include the link or reference citation for the piece and describe how it helped you better understand how fundamental
  63. chemistry

    Greg reacts 5.0 moles of hydrochloric acid(HCL)with 1.5 moles of barium hydroxide(Ba(OH)2).Which reagent is the limiting reagent, and which is in excess?If the reagent runs to completion,how many moles of barium chloride(BaCl2)will be produced? CAN SOMEONE
  64. 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
  65. Organic Chemistry

    Hello, I'm studying Organic Chemistry in College and in a homework there was an exercise that I could't resolve about aldol condensation of the same molecule. It was like this: What are the possible products of the aldol condensation of 4 molecules of
  66. Chemistry

    A single 4p orbital can hold how many electrons? i got 6 is that correct or no? Chemistry - Anonymous, Friday, September 10, 2010 at 2:52am "That is correct! px, py and pz (2 electrons in each) " since it's asking about a SINGLE 4p orbital would it be 2? i
  67. Statistics

    In how many different ways can a chemistry book, a calculus book, a history book and a dictionary be arranged on a shelf so that the chemistry book or the history book appears first?
  68. Finance

    4.A thirty year US treasury bond has a 4.0 percent interest rate.In contrast, a ten year Treasury bond has an interest rate of 2.5 percent. A maturity risk premium is estimated to be 0.2 percentage points for the longer maturity bond. Investors expect
  69. chemistry

    In Chemistry: what is ph during the titration of 20.00ml of 0.1000m triethylamine (ch3ch2)3n (kb=5.2x 10-4) with 0.1000m HCL solution after the additions of titrant : a) 0ml (b) 10.00ml (c) 19.00ml (d)15.00ml (e) 20.00ml (f) 25.00ml
  70. Chemistry

    A flask of known volume was filled with air to a pressure of 3.6atm. This flask was then attached to an evacuated flask of known volume and the air was allowed to expand into the flask. The final pressure of the air (in both flasks) was 2.7atm and the
  71. Chemistry

    When titrating 50.0 mL of 0.10 M H2SO4 with 0.10 M NaOH, how many mL of NaOH will you have added to reach the 1st equivalence point? I am confused... What H2A problem? Chemistry-Dr.Bob222 - DrBob222, Tuesday, April 12, 2016 at 1:49am Refer to the H2A
  72. Chemistry

    The question is: Isotonic saline is a 0.9% (g/100ml) solution of salty water. You are asked to make up 2L of isotonic saline. How much salt should you weigh out? I got the answer of 18g with the following working: 9 ÷ 1000(ml) x 100 = 0.9 Therefore 9% of
  73. Chemistry

    A chemistry laboratory of an experience is being conducted. The pressure is 0.9 atm and the temperature is 18°C. One of the steps of the experience requires the combustion of 500 mL ethanol (Density=0.78 g/mL). Whereas the burning of this amount of
  74. Chemistry

    A latex balloon, wall thickness 3.091 x 10-4 m, contains helium at a concentration of 0.43 kg m-3. Under these conditions the total surface area of the balloon is 0.68 m2. The diffusion coefficient of He in latex at room temperature is 4.9 x 10-9 m2s-1.
  75. polymer-Crosslinking Chemistry

    Explain why a polymer such as polybutadiene can be cross-linked, however a polymer such as polyethylene cannot be cross-linked. Make reference to what it is about the chemistry of the repeating units that allows for the formation of cross-links.
  76. English

    I forgot to include the following sentences. They are really urgent! 1) Each of you should choose a group, get a chair and start chatting with that group 2) You divide (yourselves) into groups of four and interview an American student for twenty minutes.
  77. Chemistry (creativity)

    Hey everyone. Well the part I need help in isn't exactly the chemistry part. My assignment was to research an element, and at the end, come up with some creative picture/cartoon. The problem is... I'm not exactly the creative type. My element was Mercury,
  78. Chemistry

    In what directions (on the periodic table) does atomic size increase? As you go down in a group, size increases, and as you go LEFT size increases. Size decreases as one goes right within a period.
  79. English

    I still have a few doubts on school rules. I hope you can have a look at them. It's urgent. 1)You mustn't dirnk or eat during lessons/school hours. 2) You mustn't ask questions when your teacher explains/is explaining/during explanations. 3) You must take
  80. math URGENT!!!!

    i have a list of 5 different numbers. the sum of 2 of the numbers is 0. the sum of 2 of the numbers is 1. the sum of 2 of the numbers is 2. the sum of 2 of the numbers is 3. the sum of 2 of the numbers is 4.the sum of 2 of the numbers is 5.the sum of 2 of
  81. ma

    In a class of 100 students, 40 failed in Math, 30 failed in Physics, 60 failed in Chemistry. 35 passed in both Math and Physics. 20 passed in Physics and Chemistry. 25 passed in Math and Chemistry. Each student passed in at least one subject. How many
  82. MATH! Urgent

    umm suppose a parabola has a vertex at (0,2) and points (1,1) how would I derive the equation and focus, i've been trying to understand this for so long, I can't get it. Does this parabola have the equation (y-2)^2 = x and a focus of 1/4?? Is that
  83. math

    •You and three (3) of your friends were in the same advance placement high school chemistry class in high school. All four (4) of you decided to take the same chemistry class together at the local university along with 21 other students. On the first
  84. 12 Biology! URGENT!

    Is this right: Place numbers beside the statement below to indicate the order of events occurring in the light reactions: 3 low energy electrons at PSI are re-energized by a photon of light 5 electrons energized at PSII jump to a higher lever, as they fall
  85. 12 Biology! URGENT!

    Is this right: Place numbers beside the statement below to indicate the order of events occurring in the light reactions: 3 low energy electrons at PSI are re-energized by a photon of light 5 electrons energized at PSII jump to a higher lever, as they fall
  86. Math

    At Small Town High there are 100 students, each of whom takes at least one of biology, chemistry, or physics. There are 50 students in biology, 60 in chemistry, and 70 in physics. If 24 students are enrolled in exactly two of these classes, how many
  87. Chemistry

    what are the other chemistry forms present in the dichloromethane solution besides the normal neutral forms for benzoic acid and quinine? (benzoic acid,pKa 4.2; quinnie, pKa 8.5)
  88. chemistry

    In a chemistry experiment, a student measures the density of iridium (Ir) metal as 21.52 g/cm3. The actual density of Ir metal is 22.65 g/cm3. What is the percent error of the student's measurement?
  89. chemistry... HELPP

    Chemistry Equilibrium Constant PLEASE Help!? In an experiment, equal volumes of 0.00150 M FeCl3 and 0.00150 M NaSCN were mixed together and reacted according to the equation: Fe3+ (aq) + SCN– (aq) <--> Fe(SCN)2+ (aq) The equilibrium concentration
  90. math

    Riena has six unmarked CDs in a box, where each is dedicated to exactly one of English, mathematics, French, American history, chemistry, and computer science. Answer the following questions: a. If she chooses a CD at random, what is the probability she
  91. Chemistry

    Concentration 15.8 mg/L Final Volume 100.0 mL What is the concentration of phosphate in the original lake water sample if the unknown lake water sample in the option has been diluted by taking 25.0 mL of lake water and diluting it to the indicated final
  92. MATH URGENT!!!

    A researcher is interested in the effects of monetary incentives on task performance. She recruits 60 undergraduate business students and offers to pay them each $5 for a 1 hour research session. She then randomly assigns these students to either a control
  93. set

    of 250 candidates writing a exam, 147 passed in math,150 pass in chemistry and 85 pass subjects B)calculate the number of students who pass i)pass math only ii)pass chemistry only iii)passed neither iv)pass only one subject
  94. Chemistry

    I need definitions for chemistry and I can't come up with any heterogeneous reaction homogeneous reaction activation energy activation energy activated complex elementary reaction
  95. chemistry

    A Biology student wants to know if Mountain Dew will make plants grow faster than water. As a Chemistry student, you have agreed to assist in the planning of the experiment to make sure the student designs a valid experiment. 1) What is the experimental
  96. Chemistry

    I know nothing about chemistry, but am wondering if someone could help me with these. 1) Balance this redox reaction using the oxidation-number method. Zn + O2 + HCl ® ZnCl2 + H2O 2) Balance this redox reaction using the half-reaction method. (basic
  97. chemistry

    1. Unless otherwise instructed, you may use the periodic table in the Chemistry: Problems and Solutions book for this test. You also may use the formulas on pages 238 243. A student increases the temperature of a 556 cm3 balloon from 278 K to 308 K.
  98. chemistry

    I have been having a problem with solving a chemistry problem. The problem requires finding the density in copper at 1305K (the temperature changes when you reset the problem). I think I am using the proper formula, (N_v/N_s=Ae^-changeH_v/kT). My results
  99. chemistry

    I have been having a problem with solving a chemistry problem. The problem requires finding the density in copper at 1305K (the temperature changes when you reset the problem). I think I am using the proper formula, (N_v/N_s=Ae^-changeH_v/kT). My results
  100. French (URGENT #2)

    Can someone please help check my work? There were no instructions, it is as I have written it. Am I supposed to choose only one? or more? 1. On peut pratiquer les sports décrits dans cette annonce... info: SPORTS. Cercle. Nautique. Martinique. Ski