Monday
May 2, 2016

# Posts by ChemStudent

Total # Posts: 49

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 by step.
February 24, 2015

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 by step.
February 23, 2015

Chemistry
What is the net ionic equation including phases for NiPO4(s) dissolving in H3O^+(aq) ?
June 10, 2013

chemistry
Those of you looking at this in the future don't forget the quadratic equation!!!
December 11, 2012

chemistry
the nitrate (NO3−) salt of the metal ion All nitrates are soluble.
September 19, 2012

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.
September 19, 2012

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.
September 19, 2012

Chemistry
You're in Chemistry with Prof. Kautz, right? Lol. :3
July 5, 2012

Chemistry
that is correct. The MM for Hs@ is 34.1. Closes to 5.02/0.147=34.15.
January 16, 2012

AP Chemistry
H3O+, Br1−, and water molecules
September 17, 2010

chemistry
why is fe 2+ a better reducing agent then mn2+. ( I thought since mn2+ had a higher Eox it would be better)
April 13, 2010

Thermodynamics
Perfect. I do remember reading that before. Thanks so much for the help!
February 23, 2009

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: n1...
February 23, 2009

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 level...
February 21, 2009

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 kJ/mol * 2 mol = 66.36...
February 21, 2009

Chemistry
GK, thank you so much. That was exactly what I was looking for!
February 16, 2009

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 atoms) How is the ...
February 16, 2009

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: 1170 J - 926.2 J = ...
February 6, 2009

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 unrealistically low.
February 6, 2009

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: ...
February 5, 2009

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.
November 10, 2008

Chemistry
What is the difference between acyl, acetyl, and enoyl?
November 10, 2008

math
I'd say, the answer is the product of the first three prime numbers. 2*3*5=30
November 10, 2008

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 general, and I ...
October 17, 2008

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) Calculate the ...
September 14, 2008

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 BSA gives a molecular...
September 14, 2008

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.
September 9, 2008

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 ...
September 8, 2008

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 alcohol uses "...
July 29, 2008

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.
July 29, 2008

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.
July 22, 2008

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!
July 22, 2008

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 = starting molar ...
July 22, 2008

Organic Chemistry
Perfect. Thanks!
July 22, 2008

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 washing? What gas is ...
July 22, 2008

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
July 22, 2008

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 with an aldehyde ...
July 22, 2008

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, the ether cleaves...
June 29, 2008

Chemistry
thanks!
June 24, 2008

Chemistry
Write balanced equations showing how HBr and SO2 are consumed in a gas trap containing NaOH.
June 24, 2008

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 name for 1-methyl-1-...
June 6, 2008

Chemistry
nevermind. figured it out.
June 2, 2008

Chemistry
help? is this question poorly worded? Is there no clear answer? I transcribed from my assignment directly.
June 2, 2008

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?
June 2, 2008

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 ...
May 29, 2008

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
May 28, 2008

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 are: a.(Z,Z)-5-Ethyl...
May 28, 2008

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. (E)-5-Ethyl-2,4,6...
May 28, 2008

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