drbob222

Most popular questions
  1. 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)=?

    asked by Kelsey on March 15, 2012
  2. DrBob222

    How fast should a car move toward you for the car's horn to sound 2.88% higher in frequency than when the car is stationary? The speed of sound is 343 m/s. I don't know what equation to use. I think I'm suppose to use this: fs(v-vd/v-vs) I know I got it

    asked by Jon on April 5, 2008
  3. DrBob222

    A car moving at 16.0 m/s, passes an observer while its horn is pressed. Find the difference between the frequencies of sound heard when the car approaches and when it recedes from the stationary observer. The velocity of sound is 343 m/s and the frequency

    asked by Jon on April 5, 2008
  4. DrBob222

    A boy is blowing a whistle of frequency 536 Hz and walking toward a wall with a speed of 1.64 m/s. What frequency of the reflected sound will the boy hear if the speed of sound is 343 m/s? 532 Hz

    asked by Jon on April 5, 2008
  5. DrBob222

    2N2O(g) → 2N2(g) + O2(g) d[N2O]/dt = -5.8×10-4 M/s at a particular temperature and set of concentrations. What are d[O2]/dt and d[N2]/dt? d[O2]/dt = d[N2]/dt = What is the rate of the reaction? my answer for the first one im getting -.00016 and the

    asked by Jane on September 29, 2010
  6. DrBob222

    These are the other equations I've balanced. I need help with one. AgNO3 + K2Cr2O7 --> double replacement AgNO3 + K2Cr2O7 --> AgCr2O7 + K2NO3 Please tell me if I've balanced these right. Br2 + NiI3 --> single replacement, element is a non-metal Br2 + NiI3

    asked by Derrick on July 15, 2010
  7. DrBob222

    You just answered my previous half-life question, and I was curious how to find the value of k. You said that k = 0.693/t1/2 , but how do you evaluate t sub1/2?

    asked by Sarah on April 12, 2011
  8. DrBob222

    Im in the 10th grade in Chemistry 1 Honors. Im learning to write a chemical equation. Im confuse on that statement i was given for my homework. The products and reactants are just magnesium Sulfide and magnesium and sulfur? Then why are they talking about

    asked by Christy on April 29, 2008
  9. DrBob222

    On Monday you helped me to understand and answer the one question, but I am not too sure if they want all the calculations that you answered... regretably, I am still a bit lost with these! Below is the question as it is printed: The isotope caesium-137,

    asked by Mary on February 7, 2007
  10. DrBob222

    The unique rate for the combustion of ethane is 0.44 M/s (a) what is the rate that oxygen reacts? (b) what is the rate of formation of water molecules?

    asked by tevon on May 2, 2015
  11. DrBob222

    I really want to know what this symbol means ^. I haven't learned about it at all. Does it mean squared or something?

    asked by Sara on April 20, 2010
  12. DrBob222

    True/False The medium determines the speed through which most mechanical waves will travel. True

    asked by Jon on April 5, 2008
  13. DrBob222

    Thank you very much. I appreciate it a lot.

    asked by Leigh on March 28, 2008
  14. DrBob222

    If you don't mind me asking, How are you so smart, and how old are you?

    asked by Courtney on April 7, 2010
  15. Drbob222

    Are you done helping me? Sorry, to bugg you i just reall need the help.

    asked by Courtney on April 6, 2010
  16. DrBob222

    You are creating a transverse wave in a rope by shaking your hand from side to side. Without changing the distance that your hand moves, you begin to shake it slower and slower. What happens to the wavelength? it decreases

    asked by Jon on April 5, 2008
  17. drbob222

    Thank You!

    asked by alan on February 5, 2008
  18. drbob222

    Are you available to help for a few more min. I am back. Been gone about two hours. What is it you don't understand about the former problem? Honestly I don't know what am I doing wrong or what should i be doing with the previous problem the one about

    asked by Jasmine20 on December 11, 2006
  19. DrBob222

    DrBob222 I am kind of stuck with the balancing stuff, and I already had send the post, did you not read it?

    asked by Derrick on July 15, 2010
  20. DrBob222

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

    asked by Help please on April 5, 2010
  21. DRBOB222

    THANKS so much for all of your quick and useful help!

    asked by paul on July 16, 2009
  22. DrBob222

    As a sound source moves away from a stationary observer, the number of waves will. decrease

    asked by Jon on April 5, 2008
  23. DrBob222

    A wave created when two different waves meet will have an amplitude greater than the individual waves because of. constructive interference

    asked by Jon on April 5, 2008
  24. DrBob222

    For incomplete cancellation to occur, opposite pulses must have. equal displacements

    asked by Jon on April 5, 2008
  25. DrBob222

    Moth crystals. Those round moth balls are not foam, they are napthalene, a form of benzene. were could i find moth balls because the only one's i have at home are foam balls, or is there something else with an aromatic compound in it?

    asked by bobpursley on February 5, 2007
  26. Drbob222

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

    asked by Mandy on November 27, 2010
  27. DrBob222

    I reponded back to you on my science helpers post.

    asked by Sara on April 6, 2010
  28. drbob222

    thankyou for your help its helped alot.you are a star!

    asked by dominique on October 6, 2009
  29. DrBob222

    The Doppler effect is a change in the ______of a sound. pitch

    asked by Jon on April 5, 2008
  30. DrBob222

    If a wave has a period of .02 seconds and a speed of 4 m/s, what is its wavelength? .08 m

    asked by Jon on April 5, 2008
  31. DrBob222

    For the medium to remain undisturbed as two pulses pass the same point, they must have. different amplitudes

    asked by Jon on April 5, 2008
  32. DrBob222

    What happens when a wave reaches the boundary of a new media? it would reflect back.

    asked by Jon on April 5, 2008
  33. DrBob222

    You are creating a transverse wave in a rope by shaking your hand from side to side. Without changing the distance that your hand moves, you begin to shake it slower and slower. What happens to the frequency? it decreases

    asked by Jon on April 5, 2008
  34. DrBob222

    You are creating a transverse wave in a rope by shaking your hand from side to side. Without changing the distance that your hand moves, you begin to shake it slower and slower. What happens to the amplitude? it decreases

    asked by Jon on April 5, 2008
  35. DrBob222

    Shaking a towel up and down would create what type of wave in the towel? surface

    asked by Jon on April 5, 2008
  36. DrBob222

    BTW I just want a yes, no, and/or hint for these questions to save some time. True/False Doubling the amplitude of a wave will double the amount of energy the wave can transfer. True

    asked by Jon on April 5, 2008
  37. DrBob222

    Everyone's help is greatly appreciated. I have put alot of thought into all of my answers, I may have used the incorrect formula or what have you but it happens. Now that I got that out of the way here goes the questions: True/False A wave's amplitude

    asked by Jon on April 5, 2008
  38. Drbob222

    I so need help please tell me some obscure facts about spain

    asked by Lauren F on December 7, 2007
  39. DrBob222

    are snow foam ball the same as moth balls? no. Styrofoam? Styrene is a aromatic, made from benzene. http://en.wikipedia.org/wiki/Polystyrene

    asked by claudia on February 5, 2007
  40. drbob222

    Can you check this one for me i want to make sure. The simple interest I on a principal of P dollars at Interest rate r for time t, in years, is given by I=PrT.Find the simple interest on aprincipal of $6000 at 3% for 2years. I got the following: I= 6000 x

    asked by jasmine20 on December 12, 2006
  41. drbob222

    Can you check my previous postage I'd reply already. Thank you done below What are about the other messages are they okay too. I think I just finished with all of them.

    asked by Jasmine20 on December 11, 2006