trixie

Most popular questions and responses by trixie
  1. Chemistry

    A buffer solution of volume 100.0 mL is 0.150 M Na2HPO4(aq) and 0.100 M KH2PO4(aq). Refer to table 1. (a) What are the pH and the pH change resulting from the addition of 80.0 mL of 0.0500 M NaOH(aq) to the buffer solution? pH pH change (include negative

    asked on March 16, 2010
  2. Chemistry

    Trying to name this compound and figure out its oxidation state [ CoBr2(NH3)3(H2O) ]+ I came up with triammineaquadibromocobalt(II) ion with a +3 oxidation state...but not sure if this is right... similarily for [Fe(ox)(Cl)4]3- I came up with

    asked on April 7, 2010
  3. Chemistry Question!!

    When 1.00 g of gaseous I2 is heated to 1000. K in a 1.00 L sealed container, the resulting equilibrium mixture contains 0.830 g of I2. Calculate Kc for the dissociation equilibrium below. I2 2 I What I did was converted the initial I2 into moles then

    asked on February 19, 2010
  4. Chemistry

    Calculate the initial molarity of KNH2 and the molarities of K+, NH3, OH-, and H3O+ in an aqueous solution that contains 0.75 g of KNH2 in 0.255 L of solution. You may ignore the reaction of NH3 with water. I already found the initial molarity, but I am

    asked on February 22, 2010
  5. Physical Chemistry

    When 1.00 g of gaseous I2 is heated to 1000. K in a 1.00 L sealed container, the resulting equilibrium mixture contains 0.830 g of I2. Calculate Kc for the dissociation equilibrium below. I2 2 I What I did was converted the initial I2 into moles then

    asked on February 19, 2010
  6. Chemistry

    Calculate the initial molarity of KNH2 and the molarities of K+, NH3, OH-, and H3O+ in an aqueous solution that contains 0.75 g of KNH2 in 0.255 L of solution. You may ignore the reaction of NH3 with water. I already found the initial molarity, but I am

    asked on February 23, 2010
  7. Chemistry

    A 1.00% by mass MgSO4(aq) solution has a freezing point of -0.192°C. Water has a kf of 1.86 (K·kg)/mol. (a) Estimate the van't Hoff i factor from the data. (b) Determine the total molality of all solute species. I can probably figure out the second part

    asked on February 15, 2010
  8. chemistry

    A radioactive sample contains 3.25 1018 atoms of a nuclide that decays at a rate of 3.4 1013 disintegrations per 26 min. (a) What percentage of the nuclide will have decayed after 159 d? % (b) How many atoms of the nuclide will remain in the sample? atoms

    asked on April 16, 2010
  9. algebra

    Kirk and Montega mow the soccer playing fields. They must mow an area of 500 ft long and 400 feet wide. They agree that each will mow half the area. Kirk will mow around the edge in a path of equal width until half the area is left. *What is the area each

    asked on May 8, 2008
  10. Chemistry

    A sample of pure cobalt-60 has an activity of 8 µCi. (t1/2 cobalt-60 = 5.26 a) (a) How many atoms of cobalt-60 are present in the sample? atoms (b) What is the mass in grams of the sample? g The way I approached part a was to first convert the microCi

    asked on April 16, 2010
  11. Math

    Solve the inequality: 2x-1 / 3x-2 < 1 [the < is actually less than or equal to] I got one of the answers, x is less than or equal to 1, but there's another. How do you find that answer? Thanks

    asked on February 4, 2010
  12. Reading

    i have just finished reading "A Pair of Silk Stockings" by Kate Chopin and i do not get what the story is about. can someone explain what the story is about?

    asked on January 13, 2009
  13. algebra..urgent!!!!

    MArta has $6000 to invest. She puts x dollars of this money into a savings account that earns 2% interest per year. With the rest, she buys a certificate of deposit that earns 4% per year. i need 2 different equations. [using a=prt and/or a=p(1+r/n)^nt]

    asked on February 27, 2008
  14. Chemistry

    Which of the following systems could act as a buffer? A. HCl/Cl- B. NaOH/OH- C. HSO4-/SO4-2 D. H3O+/OH- E. All of the above my guess is C because A and B are too strong, but I am unsure of D. Can someone explain how to think through this?

    asked on March 14, 2010
  15. Chemistry

    Is Zn+2 diamagnetic or paramagnetic? I am a little confused on how to figure this out and I'm finding inconsistent answers when I tried to look this up. Thanks!

    asked on April 8, 2010
  16. Physical Chemistry

    Calculate the concentrations of each of the following solutions. (a) the molality of chloride ions in an aqueous solution of iron(III) chloride for which xFeCl3 is 0.0195 (b) the molality of hydroxide ions in a solution prepared from 9.16 g of barium

    asked on February 15, 2010
  17. Chemistry

    1x10-2 mol of MgSO4 (Ksp = 9) is added to 1 L of water. Will 1x10-5 mol of CaSO4 (Ksp = 10-6) completely dissolve in the solution? I think the answer is yes...because the Q will be less than Ksp of 10^-6?? Which of the following salts would you expect to

    asked on March 16, 2010
  18. algebra 1

    a high school wrestling mat must be square with 38-foot sides and contain two circles as shown. suppose the inner circle has a radius of "s" feet and the outer circle's radius is nine feet longer than the inner circle. *write an expression for the area of

    asked on March 5, 2008
  19. Chemistry

    How much energy is emitted in each α decay of plutonium-234? (234Pu, 234.0433mu; 230U, 230.0339mu; 4He = 4.0026 mu). I tried finding the difference in mass first: (230.0339 + 4.0026) - (234.0433) = -.0068 mu I then converted from amu to kg by multiplying

    asked on April 13, 2010
  20. Chemistry

    Q1. The blood volume in a cancer patient was measured by injecting 5.0 mL of Na2SO4(aq) labeled with 35S (t1/2 = 87.4 d). The activity of the sample was 300 µCi. After 22 min, 12.9 mL of blood was withdrawn from the man and the activity of that sample was

    asked on April 16, 2010
  21. Chemistry

    I am confused about why this is the answer to a practice problem I was given. (answer is c). Could someone explain why/why not for each answer? 2) Solution A is made from 1 L of water and 0.1 moles of Na(CH3COO), and Solution B is made from 1 L of water

    asked on March 7, 2010
  22. Chemistry

    Given the equilibrium rxn CF4(g) + 2H2O(l) ⇔ CO2(g) + 4HF(g) ΔH < 0 if pressure is increased by adding argon gas to the equilibrium, I know it doesn't decrease the amount of HF. But if a random gas is added for any equilibrium rxn, will it always cause

    asked on March 9, 2010
  23. Chemistry

    A certain Geiger counter is known to respond to only 1 of every 1000 radiation events from a sample. Calculate the activity of each radioactive source in curies, given the following data. My text barely attempts to explain how to do this problem, and there

    asked on April 15, 2010
  24. Chemistry

    Calculate the pH of the solution that results from mixing the following reagents. Refer to table 1. mix 0.189 L of 0.019 M (CH3)2NH(aq) with 0.327 L of 0.011 M (CH3)2NH2Cl(aq) I tried using the Henderson-Hasselbach equation by finding the pKa but it didn't

    asked on March 16, 2010
  25. Chemistry

    100 mL of each of the following solutions is mixed; which one of the mixed solutions is a buffer? A) 1.0 M NH3(aq) + 0.6 M KOH(aq) B) 1.0 M NH4Cl(aq) + 1.0 M KOH(aq) C) 1.0 M NH3(aq) + 0.4 M HCl(aq) D) 1.0 M NH4Cl(aq) + 0.4 M HCl(aq) E) 1.0 M NH3(aq) + 1.0

    asked on March 14, 2010
  26. reading/writing

    hi i am doing a research report on proving that the animals from the past were different and more dangerous then they are now.... i have to make an outline...how can i set it up?? any ideas on an outline...plz

    asked on May 13, 2008
  27. English 10 A

    I am doing the Character Analysis Portfolio, and need to make a thesis statement, answering the following questions: Why is this character significant to the plot of the story? How does this character contribute to the development of a central theme? Could

    asked on November 4, 2016
  28. math

    cashew nuts sell for $21.00/kg. Brazil nuts sell for $15.00/k. A distributor sold a total of 120 kg of nuts and Brazil nuts for $2244. What mass of each type of nut was sold?

    asked on June 11, 2013
  29. Chemistry

    The pH of 0.50 M HBrO(aq) is 4.50. Calculate the change in pH when 6.50 g of sodium hypobromite is added to 110. mL of the solution. Ignore any change in volume. Ka of HBrO is 2E-9 I found the amount of moles used for each (.0547 mol NaBrO, and .055 mol

    asked on March 16, 2010
  30. math

    Sales clerk at an appliance store have a chance of 2 payment: Plan A: $580 every 2 weeks plus 4.2 % commission on all sales Plan B: $880 every 2 weeks plus 1.2 % commission on all sales a) Write a linear system to model this situation b) Graph the linear

    asked on June 11, 2013
  31. Chemistry

    How can you tell if [ MnCl6]4- or [ Mn(CN)6 ] 4- has the longer wavelength of light? and then how do you figure out how many unpaired electrons each has?

    asked on April 8, 2010
  32. Chemistry (or Physio/Biochem)

    Asthma affects about seven percent of the population. During an asthma attack smooth muscle cells in the bronchi constrict, the airways become inflamed and swollen, and breathing becomes difficult. What effect might an asthma attack have on blood pH? A. pH

    asked on March 14, 2010
  33. english/ literature/ essay

    hi i need help with this.. what is the importance of recognizing cultural differences as a young person in today's global society?

    asked on September 16, 2009
  34. RESEARCH REPORT

    HI I WOULD LIKE TO KNOW WHAT I CAN POSSIBLY PROVE ABOUT EITHER THE BERMUDA TRIANGLE OR ATLANTIS THE LOST EMPIRE WE AARE SUPPOSED TO PROVE SUMTHIN ABOUT EITHER OF THOSE TWO CHOICES.... I ALSO NEED SITES THAT CAN HELP ME PROVE SOMETHING ABOUT THEM

    asked on April 6, 2008
  35. algebra 1...urgent

    a high school wrestling mat must be square with 38-foot sides and contain two circles as shown. suppose the inner circle has a radius of "s" feet and the outer circle's radius is nine feet longer than the inner circle. *write an expression for the area of

    asked on March 5, 2008
  36. finance

    Chip’s Home Brew Whiskey management forecasts that if the firm sells each bottle of Snake-Bite for $20, then the demand for the product will be 15,000 bottles per year, whereas sales will be 91 percent as high if the price is raised 11 percent. Chip’s

    asked on September 28, 2013
  37. finance

    5.Capital Co. has a capital structure, based on current market values, that consists of 21 percent debt, 9 percent preferred stock, and 70 percent common stock. If the returns required by investors are 10 percent, 12 percent, and 17 percent for the debt,

    asked on September 28, 2013
  38. math

    Model this situation w/ a linear system: Melissa borrowed $10, 000 for her university tuition. She borrowed part of the money at an annual interest rate of 2.4 % and the rest of the money at an annual rate of 4.5 %. Her total annual interest payment is $

    asked on June 11, 2013
  39. algebra 2

    How do you find the points of intersection, if any, of the equations: x^2 + y^2 = 5 x - y = 1

    asked on September 6, 2011
  40. Chemistry

    One last question...even though no one seems to be willing to help me out without being rude. The blood volume in a cancer patient was measured by injecting 5.0 mL of Na2SO4(aq) labeled with 35S (t1/2 = 87.4 d). The activity of the sample was 300 µCi.

    asked on April 16, 2010
  41. Chemistry

    How can you tell if [ MnCl6]4- or [ Mn(CN)6 ] 4- has the longer wavelength of light? and then how do you figure out how many unpaired electrons each has?

    asked on April 8, 2010
  42. Chemistry

    In a .1M aq. soln of NaCN, how would you determine the major species (other than water)? And how would you determine the pH (not exact pH, I just want to know how to know if it is acidic ie.

    asked on February 21, 2010
  43. Physical Chemistry

    Calculate the equilibrium constant at 25°C and at 100.°C for each of the following reactions, using data available in Appendix 2A. Remember that the organic molecules are in a separate section behind the organic molecules in Appendix 2A. (a) HgO(s) Hg(l)

    asked on February 19, 2010
  44. science..urgent!!

    Describe what happens at the particle level and what happens to a liquid's temperature when it reaches the liquid's heat of fusion. Is it possible for the ice in your freezer to be below 0 degrees celsius? explain. When does ice in your freezer reach

    asked on March 4, 2008
  45. world history ancient greece

    i need to do an outline of how to organize things for my research report on the Ancient Olympics. How cna i divide up my report?

    asked on March 2, 2010
  46. Chemistry

    I still need help with this problem... Calculate the concentration of the solution the molality of hydroxide ions in a solution prepared from 9.16 g of barium hydroxide dissolved in 179 g of water I do not know how to approach this...I keep doing something

    asked on February 15, 2010
  47. science- bio

    how can traits on a particular chromosome be determined? how can these traits determine the characteristics of an organism? what could happen if a base is out of order?

    asked on March 26, 2009
  48. history/science

    hi. i would like to know if someone can send me websites other than wikipedia that might be able to help me find out stories of how the earth and the things on earth were made...

    asked on February 6, 2009
  49. math solvng

    if a doctor prescribes 30 units of insulin in 500 ml to be administered over 2 hours, how many drops per minute should be administered if the set is calibrated to deliver 20 drops per ml? i don't know how to get it and i need to show work...

    asked on September 9, 2008
  50. math project...PLEASE HELP...

    I am doing a math project on Leonardo Fibonacci, the creator of the Fibonacci's Sequence. I was wondering if someone could please tell me a website where I could get more information about his marriage. can someone help me?

    asked on August 22, 2005
  51. math

    Model this situation w/ a linear system: Melissa borrowed $10, 000 for her university tuition. She borrowed part of the money at an annual interest rate of 2.4 % and the rest of the money at an annual rate of 4.5 %. Her total annual interest payment is $

    asked on June 11, 2013
  52. math

    Create a linear system to model this situation. Then use substitution to solve the linear system to solve the problem. - Bobbie has been saving dimes & quarters to buy a new toy. She has a total of 28 dimes and quarters, with a value of $4.30. How many of

    asked on June 11, 2013
  53. world history

    the question is: Why is England and France developing into nations important to us? i need websites where i can get information on this please

    asked on May 3, 2010
  54. Chemistry

    A certain Geiger counter is known to respond to only 1 of every 1000 radiation events from a sample. Calculate the activity of each radioactive source in curies, given the following data. 580 clicks in 104 s My text barely attempts to explain how to do

    asked on April 16, 2010
  55. Chemistry

    for A, Z, and X I'm typing it in the form A,Z,X (or X as a particle) since I obviously can't do sub or superscript... 1,1,H + 1,1,p --> 2.1,H + ? I thought initially the missing particle at the end would be either 0,-1,e or 0,1,e (beta emission/decay) but

    asked on April 13, 2010
  56. Chemistry

    Which one of the following combinations of reagents will result in a spontaneous reaction? A) Al(s) + CuCl2(aq) B) Al(s) + CaCl2(aq) C) Zn(s) + CaCl2(aq) D) Cu(s) + ZnCl2(aq) I know the answer is A, but what I don't know is why, or how to figure this out.

    asked on April 6, 2010
  57. american lit. [[10th grade]]

    i need to write an essay about how holden caulfield from the catcher in the rye is fascinated with childhood and innocence. what can i include as examples for that?

    asked on December 1, 2009
  58. algebra review!

    it says write the equation of the vertical line that passes through the point (7,-3). what do i need to start it off? find the equation for the line with undefined slope and passing through the point (-1,-2). what do i need to start that off? what equation

    asked on September 3, 2009
  59. math/algebra

    if a doctor prescribes 30 units of insulin in 500 ml to be administered over 2 hours, how many drops per minute should be administered if the set is calibrated to deliver 20 drops per ml? i don't know how to get it and i need to show work... this is urgent

    asked on September 9, 2008
  60. MATH-Please Help me

    a menu which serves 4 people requires 3 cups of flour.how many cups of flour are needed for the menu to serve 12 people?

    asked on September 7, 2015
  61. Math

    a menu which serves 4 people requires 3 cups of flour.how many cups of flour are needed for the menu to serve 12 people?

    asked on September 7, 2015
  62. math

    use substitution to solve this linear system: 8x + y = -458 -5x + 3y = 221

    asked on June 11, 2013
  63. math

    Explain what happens when you try to solve this linear equation using an elimination strategy. What does this tell you about the graphs of these equations? -8x + 20y = -40 24x - 60y = 120

    asked on June 11, 2013
  64. math

    write an equation in general form for the line that passes through A(3,-4) and B(11, 8)

    asked on June 11, 2013
  65. us history

    how was president Woodrow Wilson truly a progressive president?

    asked on September 23, 2010
  66. Chemistry

    If a weak acid is say only 5% ionized at equilibrium, then the ionization rxn would be reactant favored, correct? I am a little on the fence about understanding this if anyone could better explain why this would be? I am assuming because it is not

    asked on March 9, 2010
  67. Physical Chemistry

    Determine the temperature change when 18.0 g of the following salt is dissolved in 190. g of water. The specific heat capacity of water is 4.184 J·K-1g-1. The enthalpies of solution in the table are applicable. Do not take the added mass of the salt into

    asked on February 10, 2010
  68. algebra review

    find the y-intercept of a line that passes through (2,1) and has a slope of -5. i forgot what equation i have to use to find this out. can someone give me which equation i have to use? or all the equations that deal with slopes please

    asked on September 3, 2009
  69. not sure wat subject

    i need two examples of situations where you would think help/charity should be given but it didn't happen as you thought

    asked on February 25, 2009
  70. vocabulary->sentences

    hi... umm i need a sentence for "confines" which means the limit of space or area,borders,boundaries

    asked on March 4, 2008
  71. algebra 1

    MArta has $6000 to invest. She puts x dollars of this money into a savings account that earns 2% interest per year. With the rest, she buys a certificate of deposit that earns 4% per year. i need 2 different equations. [using a=prt and/or a=p(1+r/n)^nt]

    asked on February 27, 2008
  72. algebra

    the teacher accendentally reversed the digits if a test scored and shorted a student 36 points. SHe told the students that the sum of tha digits was 14. what was the actual score on the test? i need two equations

    asked on January 6, 2008
  1. math

    please get back asap

    posted on June 11, 2013
  2. math

    no idea . please help!

    posted on June 11, 2013
  3. math

    is the answer 3x -2y -17= 0?

    posted on June 11, 2013
  4. math

    will it work if i write : they have the same slope and are identical. Both have the slope of 2/5?

    posted on June 11, 2013
  5. world history

    i don't get the question because at the time in which they developed, the US didn't even exist.

    posted on May 3, 2010
  6. Chemistry

    I figured out the first one...still struggling with the 2nd...

    posted on April 16, 2010
  7. chemistry

    Could you please just explain what I am doing wrong so that I can know how to approach these problems? I appreciate the advice and am well aware I need to go to bed...but I have to get these finished and my professor is out of town attending a memorial

    posted on April 16, 2010
  8. Chemistry

    I also posted the above well before Dr. Bob had answered one of my other questions...

    posted on April 16, 2010
  9. chemistry

    Sleep is a bit of a luxury.....unfortunately I'm one of those students that doesn't have an option of taking a lighter load or working less....luckily I graduate in a few weeks. In the meantime I need to finish these problems so that I can go to bed....but

    posted on April 16, 2010
  10. Chemistry

    I wasn't talking about DrBob being rude...that would be bobpursely...DrBob has been nothing but helpful while I have used this site as a resource.

    posted on April 16, 2010
  11. chemistry

    Another attempt I made gave me relatively "reasonable" answers...but still doing something wrong. I converted the minutes to days and used that in the rate to find k via k= rate/N ; N being 3.25E18 atoms. this calculated k to be .00145. I plugged this into

    posted on April 16, 2010
  12. chemistry

    Oh and when I try to put this into my calculator I get 0... sorry if I am not catching on fast enough for some....I worked graveyard last night and Haven't slept in over 35 hours...

    posted on April 16, 2010
  13. Chemistry

    Hmm...I don't know. My webassign is telling me it's not a neutron. Thanks

    posted on April 14, 2010
  14. Chemistry

    Oh i just realized how you typed the equation has the product flipped. so it's 1,1,H + 1,1P --> 2,1H + ? order is A,Z,X where A is mass and X is the particle or element

    posted on April 13, 2010
  15. Chemistry

    neutron was my first answer...i am using +1 e^0 to be a positron though, not electron.

    posted on April 13, 2010
  16. Chemistry

    Nevermind...I realized that the problem I was using as an example called for 1 g of the reactant used....this didn't....so I have my correct answer now. Thanks! Still stumped on my earlier question though...

    posted on April 13, 2010
  17. Chemistry

    no problem :)

    posted on April 13, 2010
  18. Chemistry

    Think of the equations you have learned and which variables you have been given. It helps to keep a list of them in front of you so you can quickly figure it out. Then just plug in. If you have P, V, mass, and T....you're going to use PV=nRT...just solve

    posted on April 13, 2010
  19. Chemistry

    I know they need to balance out on both sides. I am just confused because I am pretty sure it should be 0,+1, e ...e being X. Webassign is telling me this is wrong but if that's true I don't understand why and need that explained....

    posted on April 13, 2010
  20. Chemistry

    You know it's second order so your rate=k[NO2]^2 All you do is like you said, find moles, use that to find molarity (convert mL to L) and then plug the concentration into the equation. You're given the k. Same thing with part B, just changing the

    posted on March 31, 2010
  21. Chemistry

    All you have to do is find the concentration of OH- and solve for pH (pOH= -log [OH-] nad then 14-pOH=ph [OH-} = Ksp/[M+}

    posted on March 19, 2010
  22. Chemistry

    NVM i was using the pKA instead of pH....i had it right afterall...guess it's just time for bed....

    posted on March 17, 2010
  23. Chemistry

    I figured out the correct new pH for each respective part, but apparently the initial pH i found for the buffer solution is incorrect. I just need help in figuring that so I can calculate the change. I initially thought the buffer pH was 7.38. Thanks!

    posted on March 17, 2010
  24. Chemistry

    for part a I tried using the HH equation, found moles of NaOH and used that for [base] and moles Na2HPO4 as [acid]...i used pKa 7.21...that was incorrect. For part b I used a similar method...plugging in HNO3 as the [acid] and Na2HPO4 moles as [base] the

    posted on March 17, 2010
  25. Chemistry

    I'm confused how I would use the Ka equation in the HH equation??? I thought HH was just pH=pka + log([base]/[acid]) ...

    posted on March 16, 2010
  26. Chemistry

    Nevermind I got it...I just mixed up my variables a little. thanks!

    posted on March 16, 2010
  27. Chemistry

    I am pretty stuck...not sure if I used the Henderson-Hasselbach the right way and I'm a little confused on how to set up the Ka expression...

    posted on March 16, 2010
  28. Chemistry

    I am trying to use pH=pKa + log(acid/base) to see where that gets me...I'm attempting to find the [base] using the given pH and pKa of 8.69 (for HBrO)...then use the concentration to find the new pH...

    posted on March 16, 2010