chemstudent

Most popular questions and responses by chemstudent
  1. chemistry

    A sample of 1.00 mol H2O(g) is condensed isothermally and reversibly to liquid water at 100°C. The standard enthalpy of vaporization of water at 100°C is 40.656 kJ mol−1. Find w, q, ∆U, and ∆H for this process. ------------- I can solve for ∆H: n

    asked on February 5, 2009
  2. Thermodynamics

    What is the temperature of a two-level system of energy separation equivalent to 300 cm^−1 when the population of the upper state is one-half that of the lower state? What does this "energy separation equivalent to 300 cm^−1" mean? I can get this far:

    asked on February 23, 2009
  3. Chemistry

    Solid NaI is slowly added to a solution that is .010M in Cu+ and .010M in Ag+... a.) which compound will precipitate first b.) calculate [Ag+] when CuI just begins to precipitate c.)what % of Ag+ remains in solution.

    asked on September 9, 2008
  4. Chemistry

    Calculate the entropy change in the surroundings when 1.00 mol N2O4(g) is formed from 2.00 mol NO2(g) under standard conditions at 298 K. I get +192 J/K. The book says -192 J/K. Here is my work, where am I going wrong? Standard Enthalpy of NO2(g) = 33.18

    asked on February 21, 2009
  5. Chemistry

    A quantitative amino acid analysis reveals that bovine serum albumin (BSA) contains 0.58% tryptophan (Mr 204) by weight. A) Calculate the minimum molecular weight of BSA (i.e. assume there is only one Trp residue per protein molecule) B) Gel filtration of

    asked on September 14, 2008
  6. ElectroChem

    Find the Emf for the cell Cr(gr) | Sn4+(aq, .059 M), Sn2+ (aq, .059 M) || Fe3+ (aq, .15 M), Fe2+ (aq, .015 M) | Pt(s) if the standard cell emf is .77 V at the cathode and .15 V at the anode. Answer in Units of V. If would be nice if you could show me step

    asked on February 24, 2015
  7. ElectroChem

    Find the Emf for the cell Cr(gr) | Sn4+(aq, .059 M), Sn2+ (aq, .059 M) || Fe3+ (aq, .15 M), Fe2+ (aq, .015 M) | Pt(s) if the standard cell emf is .77 V at the cathode and .15 V at the anode. Answer in Units of V. If would be nice if you could show me step

    asked on February 23, 2015
  8. chemistry

    why is fe 2+ a better reducing agent then mn2+. ( I thought since mn2+ had a higher Eox it would be better)

    asked on April 13, 2010
  9. Chemistry

    Write balanced equations showing how HBr and SO2 are consumed in a gas trap containing NaOH.

    asked on June 24, 2008
  10. Chemistry - Second Try

    Is this the wrong forum for these type of questions or can I improve the way I'm asking. If so, let me know. Thanks :) ------------- A quantitative amino acid analysis reveals that bovine serum albumin (BSA) contains 0.58% tryptophan (Mr 204) by weight. A)

    asked on September 14, 2008
  11. Chemistry

    Which mechanism can better account for the product mixture obtained from the dehydration of cis and trans 4-methyl-cyclohexanol: E1, E2, or a combination of the two?

    asked on June 2, 2008
  12. Chemistry

    Why is rubbing alcohol poisonous? Some rubbing alcohols are made from isopropyl alcohol which you clearly can't drink, but most rubbing alcohol is made from ethanol and water which are the same ingredients in alcoholic beverages. I hear that rubbing

    asked on July 29, 2008
  13. Chemistry

    Show the mechanism that illustrates the following reaction. 1-methyl-1-methanol-cyclopentane + acid -> 1-methyl-cyclohexene So, there is an elimination reaction, *AND* the carbon ring grows from a five carbon ring to a six carbon ring. (I hope my IUPAC

    asked on June 6, 2008
  14. Organic Chemistry

    isopentyl alcohol is reacted with acetic acid to make isopentyl acetate through Fischer esterification. Sulfuric acid is used to assist the reaction. After the reaction, the solution is washed with sodium bicarbonate. What reactions take place during this

    asked on July 22, 2008
  15. Chemistry

    What is the net ionic equation including phases for NiPO4(s) dissolving in H3O^+(aq) ?

    asked on June 10, 2013
  16. Chemistry

    I'm working with a reaction of the form: A + B -> C Problem: IF the equilibrium constant is 4.2 and an equimolar mixture of A + B are reacted, verify that there will be an equilibrium yield of 67%. Here is my attempt thus far. 4.2 = [C] / ([A]*[B]) x =

    asked on July 22, 2008
  17. Chemistry

    A sample of an ideal gas consists of 2 moles, pressure = 1 atm, volume = 0.5 liters Find the temperature pV=nRT T = p*V/(n*R) T = 1 atm * 0.5 liters / (2 moles * .08206 L atm K^-1 * mol^-1) T = 3.04 K Did I do that problem correctly? That temperature seems

    asked on February 6, 2009
  18. Chemistry

    The question asks to determine the IUPAC name of a compound based on a diagram. I would choose the name: (Z)-5-ethyl-2,4,6-trimethyl-2,4-octadiene However, this doesn't match any of the given choices. They are: a. (Z,Z)-5-Ethyl-2,4,6-trimethyloctadiene b.

    asked on May 28, 2008
  19. Chemistry

    The general formula for moment of inertia is: I = Sigma mi * ri^2 (mi is mass of atom, ri is distance to axis of rotation) In a diatomic molecule, the moment of inertia is I = ma*mb(ma+mb) * R^2 (R is distance between atoms, ma and mb are masses of two

    asked on February 16, 2009
  20. Tutoring Question

    I love this jiskha service so far. It's been extremely helpful, however I was wondering if there were pay services that offered a little more. Sometimes I don't get answers to homework problems I'm stuck on. I think it's harder to get help on some college

    asked on February 21, 2009
  21. Chemistry

    What is the difference between acyl, acetyl, and enoyl?

    asked on November 10, 2008
  22. Chemistry

    What is the difference between these two compounds: (Z)-5-Ethyl-2,4,6-trimethyl-2,4-octadiene (Z)-5-Ethyl-2,4,6-trimethyloctanadiene Which is the correctly formed IUPAC name? What does the "na" mean in "nadiene"? Why does the latter name, not specify the

    asked on May 29, 2008
  23. Chemistry

    I understand the basics of HBr/HI cleavage of ethers. Ether: R-O-R' When both substituents are primary or secondary, cleavage occurs by SN2. Br- or I- attack less hindered substituent. when one of the ether substituents is tertiary, benzyllic, or allylic,

    asked on June 29, 2008
  24. Chemistry

    I'm looking at a protein in a 3D visualization program (PyMol). I have the full amino acid sequence list. How do I determine *where* there are hydrophobic interactions that are stabilizing the tertiary structure? I know what hydrophobic interactions are in

    asked on October 17, 2008
  25. Chemistry

    Why is "phenyl" the name for the substituent variant of a benzene ring and "benzyl" refers to something slightly different (-CH2-Ph)? Also, since phenylalanine has a benzyl side-group, why isn't it called benzylalanine? Are these inconsistencies due to

    asked on September 8, 2008
  1. chemistry

    CrPO4 and Pb(OH)2 All nitrates are soluble, so LiNO3 would dissolve. Sodium & potassium salts are soluble, so NaBr and KOH are out. Chlorides in this case are soluble, so RbCl is out, leaving the other two.

    posted on October 2, 2013
  2. chemistry

    Ni(OH)2, Mg(OH)2 This is what I think: Solubility rules say all hydroxides are insoluble except for compounds of Group 1 elements, so LiOH and KOH are not the answer. Calcium is moderately soluble, leaving the other two.

    posted on October 2, 2013
  3. chemistry

    the nitrate (NO3−) salt of the metal ion All nitrates are soluble.

    posted on October 2, 2013
  4. AP Chemistry

    H3O+, Br1−, and water molecules

    posted on October 2, 2013
  5. chemistry

    3. PbS

    posted on October 2, 2013
  6. chemistry

    Those of you looking at this in the future don't forget the quadratic equation!!!

    posted on February 26, 2013
  7. math

    You're in Chemistry with Prof. Kautz, right? Lol. :3

    posted on July 5, 2012
  8. Chemistry

    that is correct. The MM for Hs@ is 34.1. Closes to 5.02/0.147=34.15.

    posted on January 18, 2012
  9. Thermodynamics

    Perfect. I do remember reading that before. Thanks so much for the help!

    posted on February 23, 2009
  10. Chemistry

    GK, thank you so much. That was exactly what I was looking for!

    posted on February 16, 2009
  11. CHEM-vaporization

    The iron will lose this much energy upon cooling to 100C: .45 J*g^-1*K^-1 * 50g * 52K = 1170 J The water will gain this much energy when heating to 100C 4.21 J*g^-1*K^-1 * 20g * 11K = 926.2 J The difference in those energies will be used to vaporize water:

    posted on February 6, 2009
  12. Chemistry

    I already googled and read those exact pages before posting. Acyl and Acetyl look like the exact same thing yet they have completely different Wikipedia pages. I get the feeling that there is some difference that I am not seeing.

    posted on November 11, 2008
  13. math

    I'd say, the answer is the product of the first three prime numbers. 2*3*5=30

    posted on November 10, 2008
  14. MATH

    Each choice properly multiplies up to 1386, but D is the only choice that has all prime factors. 693, 231, and 33 aren't prime numbers since they can be factored further.

    posted on July 29, 2008
  15. Chemistry

    The problem I have with this is, that if I change the initial 1 concentration to something else, like 2 for example, then x/2 solves to a different yield % (71%). This leads me to believe that there is no constant yield percent for the given problem.

    posted on July 22, 2008
  16. Chemistry

    Thanks so much. I thought I was missing something, but you are right. Either I'm misreading the problem or it can't be solved from the information provided. I'll turn that in. Thanks!

    posted on July 22, 2008
  17. Organic Chemistry

    Perfect. Thanks!

    posted on July 22, 2008
  18. Organic Chemistry

    1-hexanal is redundant. In an aldehyde, the aldehyde carbon is always #1. After seeing DrBob's answer, I'd change the substituent orders in my answer to be alphabetic: 2-ethyl-3-hydroxyhexanal 2-ethyl-1-hydroxyhexan-3-one 2-ethyl-1-formylhexan-3-one

    posted on July 22, 2008
  19. Organic Chemistry

    If primary alcohol is oxidized once, you get an aldehyde group (if oxidized twice you would get a carboxylic acid) 2-ethyl-3-hydroxyhexanal If secondary alcohol is oxidized, you get a ketone: 1-hydroxy-2-ethylhexan-3-one If both oxidize, you have a ketone

    posted on July 22, 2008
  20. Chemistry

    thanks!

    posted on June 24, 2008
  21. Chemistry

    nevermind. figured it out.

    posted on June 3, 2008
  22. Chemistry

    help? is this question poorly worded? Is there no clear answer? I transcribed from my assignment directly.

    posted on June 3, 2008
  23. Chemistry

    I was hoping you could envision the molecule given my estimated IUPAC name of: (Z)-5-ethyl-2,4,6-trimethyl-2,4-octadiene

    posted on May 29, 2008
  24. Chemistry

    (I think my tabs broke that post. retrying...) The question asks to determine the IUPAC name of a compound based on a diagram. I would choose the name: (Z)-5-ethyl-2,4,6-trimethyl-2,4-octadiene However, this doesn't match any of the given choices. They

    posted on May 28, 2008