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December 20, 2014

Posts by K


Total # Posts: 768

Organic Chemistry-pls check
"A" was correct
February 24, 2008

Organic Chemistry-pls check
I think that it must be "a", too, when I rethought it. Thank you.
February 24, 2008

Organic Chemistry-pls check
Which is the major product from acid catalyzed hydration (addition of water) of 2-methyl-2-pentene? a) 2-methyl-2-pentanol b) 2-methyl-1-pentanol c) 2-methyl-3-pentanol d) 3-methyl-3-pentanol answer: "c": 2-methyl-3-pentanol ???
February 24, 2008

Organic Chemistry
ignore this post.
February 24, 2008

Organic Chemistry
should it be: 2-chloropentane & 1,2-dichloropentane??? ie. "D" ??? I don't think that it could be "I or III"
February 24, 2008

Organic Chemistry
I am really not certain on the following question: Which compounds contain stereocenters?? I) 1-chloropentane II) 2-chloropentane III) 3-chloropentane IV) 1,2-dicloropentane a)-> I, II b)-> III, IV c)-> I, III d)-> II, IV I) 1-cloropentane has sterocenters...right?
February 24, 2008

Organic Chemistry
ignore this post.
February 24, 2008

Organic Chemistry
I just want to check if I am correct on this Q: What is the major product formed when 1-butene reacts with water in the presence of dilute sulphuric acid? a) 1-butanol b) 2-butanol c) butane d) 1-methylpropanol I "think" that it "should" be "B" (2...
February 24, 2008

Chemistry
I'm struggling with this homework question: Draw all possible isomers you can for C4H8O2. So far I have three esters and butanoic acid, is that correct? I'm not sure if I completely understand this question.
December 16, 2007

math..please help
Factor 5A^4 - 5A
December 12, 2007

MATH
Factor 5A^2 - 5A
December 12, 2007

Chemistry
Do impurities raise or lower the property of an organic compound such as lower or raise an equivalent weight?
December 3, 2007

English Grammar
always should be an adverb...describing what the action is which is the verb "late". Try that, it "should" be correct.
December 3, 2007

CHEM
I did manage to get as far as the 380.5pm's. I guess where I did go wrong is that I missed carrying it further than that. I missed the 380.5*sqrt 2=538.1pm's & then the remainder of the answer. Thank you very much. It's good to know that I was getting the handle of...
December 3, 2007

CHEM -DrBob222 if possible
I ran out of attempts but I still would like some help trying to figure out how to do this question properly, please.
December 3, 2007

CHEM -DrBob222 if possible
I tried exactly what I had done with the above & got my answer to be: 190.2pm's & was still wrong!! Could you please guide me as to what I should be doing? I only have 2more attempts left at the question.
December 3, 2007

CHEM
I think that I used Robidium's atomic mass instead of Rdodium's...I'll check now if that works better. Does it look as though I am on the right track though??
December 3, 2007

CHEM
oh yes...the answer should look like this: r = _____pm
December 3, 2007

CHEM
Rhodium has density of 12.41g/cc and crystallizes with the face-centered cubic unit cell. Calculate the radius of a rhodium atom. xpress your answer using four significant figures. For this question I tried to calculate backwards from a previous question I had asked this past ...
December 3, 2007

CHEM****DrBob222
this worked out perfectly!...thank you...that was the last question for the year that I had to finish through that program. I really must not have been paying attention with "a*2", as opposed to dividing a/2 to solve for "r". Thank you again, & for having ...
November 30, 2007

CHEM****
& for #2 (with the gold/Au): Volume = (407pm)^3??? = 67,419,143 (or: 6.74 * 10^7)?? then does 6.74*10^-7pm's translate to: 6.74*10^+10 cm's?? Then go something like: (4 atoms)(196.967g/mol Au)/6.02*10^23 atoms mol-1 = 1.30875*10^-21 g?? Then density = mass/volume: d = ...
November 30, 2007

CHEM****
Initial info: The atoms of crystalline solid pack together into a three-dimensional array of many small repeating units called unit cells. The simplest of the unit cells are those that have cubic symmetry, with atoms positioned at the corners of a cube. Atoms can also be found...
November 30, 2007

math
3/5 = x/15 find the common denominator which will be "15" then, since you multiply the "5" by "3" to get "15", then you must multiply the top, numerator, by the same. Therefore: 3*3 = "9" If you had: 4/5 to get a full set of 15...
November 30, 2007

Language Arts/Capitalization
I would go for capatilizing the "C" on "Club" in this case. If you are saying: "I attended a Christian club," then the "c" would be lower case. However, if you are saying: "I go to Christian Club," then I "believe" ...
November 30, 2007

Math
perhaps attempt to show him some practical/real world examples where understanding simple division is a tremendous asset. Go over dealing with $, that may get him interested...or find something that he is a huge fan of & somehow apply division to that. You could also make up ...
November 30, 2007

English
Thank you for your time and attention in this matter.
November 29, 2007

CHEM
Info: The atoms of crystalline solid pack together into a three-dimensional array of many small repeating units called unit cells. The simplest of the unit cells are those that have cubic symmetry, with atoms positioned at the corners of a cube. Atoms can also be found in the ...
November 29, 2007

CHEM
I will send a msg to the site & see what I receive back. I figure that D should have been correct initially, but I picked C instead by accident...it came up with the feedback stmt & I got more confused.
November 28, 2007

CHEM
The answer was B
November 28, 2007

CHEM
You are a researcher for a golf club manufacturer. You are given two identical looking cubes of a metal alloy. You are informed that they are made of the exact same material, but one is a crystalline, while the other is amorphous. It is your job to determine which one is ...
November 28, 2007

CHEM
I tried drawing as this & it turned out to be correct. Thank you very much!
November 26, 2007

CHEM
is trigonal planar bent though? or would it basically look just as you have it, but with 2electrons on top of the "O" & 2 on the bottom of it? & then 6/3pairs of electrons around the "Cl". or...being as how these structures are way too hard to type out: the...
November 26, 2007

CHEM
One other question that I am really not 100% sure on: how do I draw the electron-dot structure for: CHClO. I "think" that CHClO is a trigonal planar molecule, with the central atom being carbon. Is this correct?
November 26, 2007

CHEM
yes...I guess they were looking for #3.
November 26, 2007

CHEM
If the four F atoms are in the equatorial positions and the two Cl atoms are axial, all polar bonds cancel. This is what it said when I had tried "always polar"...I had selected the wrong answer. So...it is either then, as I had originally thought: "always non-...
November 26, 2007

CHEM
Which statement best describes the polarity of SF_4Cl_2?? (or: SF4Cl2, if that helps more) 1. Always polar. 2. Always nonpolar. 3. Depending on the arrangement of outer atoms, this molecule could be polar or nonpolar. & how can you tell for certain??? I think that it might be...
November 26, 2007

CHEM
The answer was "e"...I had to include the 120-degrees as well.
November 26, 2007

CHEM
Ok...I really don't have much of a clue now. "f" was also incorrect. So...does this problem need me to add 120-degrees in there then as well: "e"- 90, 120, & 180...or am I seriously still way off!!!
November 26, 2007

CHEM
I tried for "d" 90-degrees only & it stated the following: Also consider the angle between the equatorial atoms. would this then be: "f" 90 & 180 degrees?? I don't see where 120-degrees plays in this structure & I am obviously missing another to add to ...
November 26, 2007

CHEM
What are the expected bond angles in ICl4+ (or) ICl_4^+ ?? I think that I have the stucture drawn correcty: I is the central atom with one lone pair above it. I then have the Cl's with 6dots around them & then bonded, singly, to the "I". Two "Cl's" ...
November 26, 2007

CHEM
I got the answer correct!!...It was BP-BP < LP-BP < LP-LP
November 26, 2007

CHEM
kind of need some guidance with "PART C" below: A) The bond angles in CH4 are 109.5degrees, while the bond angles in NH3 are 107 degrees. Based on this information, which type of repulsion must be greater: BP-BP LP-BP ((((for this part I got: "LP-BP" as ...
November 26, 2007

CHEM
I kind of need some guidance with "PART C" below: A) The bond angles in CH4 are 109.5degrees, while the bond angles in NH3 are 107 degrees. Based on this information, which type of repulsion must be greater: BP-BP LP-BP ((((for this part I got: "LP-BP" as ...
November 26, 2007

CHEM
"C"...sp^2 was correct, i couldn't find what this compound was either.
November 26, 2007

CHEM
What is the hybridization of the central atom in COH2?? Would the correct response, out of the following: a) sp b) sp^2 c) sp^3 d) sp^3d e) sp^3d^2 "e"-> sp^3d^2??
November 26, 2007

CHEM
I figured out this problem. I ended up just putting the charges on each atom.
November 26, 2007

CHEM
If NO3- has 3 resonance structures, but only one has to be written, where does the extra electron, making there then be 24 electrons, go if you cannot put brackets around the structure you are drawing? Do you put -1 on both of the singly bonded Oxygens?...or where should the ...
November 26, 2007

CHEM
For a molecule of fluorous acid, the atoms are arranged as HOFO. What is the formal charge on each of the atoms? Enter the formal charges in the same order as the atoms are listed. For this question I tried entering: +1,-2,+3,-2 and it was wrong...as was: +1,-2,-1,+2 what ...
November 26, 2007

CHEM (DrBob222)
I had posted the question to that previous chem question, regarding Mo & V...they said that it should have been correct. What I am thinking that I was missing...must have been that I did not include 4s & then just not fill it. I had excluded it from my electron filling ...
November 26, 2007

CHEM
Which answer best describes an O_3/ozone molecule: 1. Each atom in ozone is connected to another atom by 1.5 bonds. 2.The double bond in ozone switches back and forth between the two outer oxygen atoms. 3.An ozone molecule contains one single bond and one double bond. I want ...
November 26, 2007

Art
Is a natural painting also a representational one?
November 20, 2007

CHEM
I ran out of attempts. I am going to attempt to ask under the "help" to see what they say.
November 13, 2007

CHEM
I tried 1s2, 2s2, 2p6, 3s2, 3p6, 3d2 as well, it did not work either.
November 13, 2007

CHEM
I just have one more question regarding electron configurations for the following ions: Mo^3+ V^3+ I cannot understand why my answers are not working. Not listing as ground-state configs, but as full e- configs: shouldn't Mo^3+ be: 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p6, ...
November 13, 2007

Quick general Q:
You are all very welcome, it was very sincere. The part about the Girl Scouts, aside from all of your other work tremendous work, is terrific! (I was a Girl Guide for 10yrs & my mother has been a main GG leader for the past 19yrs now.)
November 13, 2007

Quick general Q:
Well, I must say then... to all of you whom help each and everyone of the students who use this site, myself included, are very incredible & extraoridinary for taking time out of your busy lives to help everyone!! Thank you to all!!! It does not go unnoticed!!
November 13, 2007

Quick general Q:
Is there any way that people are able to send charitable monetary donations, of sorts, for all of the help & guidance which they receive through this site?
November 13, 2007

**CHEM
Place the following elements in order of Decreasing atomic size: tellurium, bromine, argon, cesium, strontium, and selenium. would the correct ranking then be: Cs, Sr, Te, Se, Br, Ar ??? or am I still way off??
November 13, 2007

CHEM**
I am going to take the above down. Again, thank you.
November 13, 2007

CHEM**
this ordering came up as being correct. Thank you for your time, it's much appreciated!
November 13, 2007

CHEM**
you have them as: 0.98, 1.14, 1.17, 1.36, 1.91, 2.35 so...does this mean that: Cs=2.35, Sr=1.91, Te=1.36, Se=1.17, Br=1.14 & Ar=0.98 ??? Therefore this order is then correct, as in being listed in order of Decreasing atomic size?? (this isn't the same as in order of ...
November 13, 2007

CHEM**
Place the following elements in order of Decreasing atomic size: tellurium, bromine, argon, cesium, strontium, and selenium. would the correct ranking then be: Cs, Sr, Te, Se, Br, Ar ??? or am I still way off??
November 13, 2007

CHEM**
ignore the "At"...it was supposed to be "Ar-argon"
November 13, 2007

CHEM**
I just have 2 other questions that I just want to make sure on: Place the following elements in order of decreasing atomic size: tellurium, bromine, argon, cesium, strontium, and selenium. (Te, Br, Ar, Cs, Sr, Se) ~~(or...the correct ranking cannot be determined)~~ I think ...
November 13, 2007

**CHEM**
this order came up being correct. Thank you
November 13, 2007

**CHEM**
Arrange the following elements in order of decreasing atomic radius: Cs, Sb, S, Pb, Se *(list from largest to smallest...or..."the correct ranking cannot be determined") ***I think the answer 'should be', from largest to smallest: ***Cs, Pb, Sb, Se, S***???? ...
November 13, 2007

CHEM
the 4th one was correct as well. Thank you!
November 13, 2007

CHEM
Could someone please tell me if I am correct on the following???: Pick the larger species from each of the following pairs. Sr or Sr^2+ *(I think it is Sr) N or N^3- *(I think it is N^3-) Ni or Ni^2+ *(I think it is Ni) S^2- or Ca^2+ *(I think it is S^2-)
November 13, 2007

CHEM
Z wasn't correct. Element Z has a larger radius than elements X and Y. Because the outer electrons of element Z are not attracted as tightly to the nucleus as the outer electrons of elements X and Y, we can expect element Z to have a lower first ionization energy than ...
November 13, 2007

CHEM
Which of the following elements has the highest first ionization energy? Element then radius (pm): X = 105pm Y = 175pm Z = 274pm I think that the answer is "Z-274pm", but I just would like to make sure.
November 13, 2007

CHEM
Consider the following neutral electron configurations in which 'n' has a constant value. Which configuration would belong to the element with the most negative electron affinity, E-ea? a) ns^2 b) ns^2 np^2 c) ns^2 np^5 d) ns^2 np^6 would the answer be "d"...
November 13, 2007

CHEM
Consider the relation shown for the radius of the species indicated. Which choice presents a valid comparison? a) Na > Na+ b) Ca^+2 > Ca+ c) Cl > Cl- d) S- > S^2- I think that the answer is "a"...but not 100% certain. pls help.
November 13, 2007

CHEM
if you were to draw a Lewis dot structure for HOCl...would it be H:Cl:O: (with double dots above & below the Oxygen & Chlorine) or would it be: H:O:Cl: (same thing for the double dots being above & below the Cl & O? Basically...is Oxygen the central atom in this case or is Cl ...
November 10, 2007

CHEM
WOOO! 3.12*10^4 came to be correct indeed! Thank you ever so much for your time & patience.
November 5, 2007

CHEM
so just divide by 1000? I tried that when I had 5.19*10^-20 & it told me I was incorrect? or did you mean to divide somewhere else along the way?
November 5, 2007

CHEM
where am I going wrong?
November 5, 2007

CHEM
apparently 5.18*10^-17 kJ/mol isn't the correct answer either.
November 5, 2007

CHEM
Soooo??? KE = hc/lambda - 1.602*10^-19J*956eV?? 6.6261*10^-34*3.0*10^8 / 9.7*10^-10m minus 1.53*10^-16?? =5.19*10^-17??? That can' be right??
November 5, 2007

CHEM
the answer came to 3.2*10^-35m. I kept typing the values into the calculator wrong. I multiplied the 765m/s, rather than dividing. I still don't understand the other question though. Q#2.
November 5, 2007

CHEM
I just have a couple of questions that I need some help with: 1) A 0.22-caliber handgun fires a 27g bullet at a velocity of 765m/s. Calculate the de Broglie wavelength of the bullet. Express your answer using two significant figures in meters. ~and~ 2) An X-ray photon of ...
November 5, 2007

CHEM
2.0*10^-34 was correct. Thank you.
November 5, 2007

CHEM
so...would I find the answer to be: lambda=6.626*10^-34 J s/(0.0459kg)(72.0m/s) answer= 2.00*10^-34 or should I have squared the 72.0m/s velocity?
November 5, 2007

CHEM
The mass of a golf ball is 45.9g. If it leaves the tee with a speed of 72.0 m/s, what is its corresponding wavelength? Express your answer numerically in meters. Would the correct answer be: lambda=h/mv lambda=6.626*10^-34/(45.9g)(72.0m/s) lambda=2.00*10^-37 ??? Is the ...
November 5, 2007

unsramble words
1. secret 2. search 3. new finder?? 4. dwindce?? dwinced??...not sure if those are words so much.
November 4, 2007

CHEM
guess it was correct... the real answer, rounded though, came to be: -2.05*10^-18J thank you.
November 4, 2007

CHEM
I used: E = -(Rhc)/n^2 R= 1.097*10^7 m^-1 h= 6.6261*10^-34 J s c= 3.00*10^8 m s^-1 E= -(1.097*10^7)(6.6261*10^-34)(3.00*10^8)/16 E= -1.36*10^-19 J so I just use final minus initial? How so? when I do the same as above...but put in 1squared=1, rather than 4squared=16.. I get: -...
November 4, 2007

CHEM
The electron from a hydrogen atom drops from an excited state into the ground state. When an electron drops into a lower-energy orbital, energy is released in the form of electromagnetic radiation. Part A: How much energy does the electron have initially in the n=4 excited ...
November 4, 2007

CHEM
thank you..I reworked it & the answer came to: 0.73%.
November 4, 2007

CHEM
The mass of an electron is 9.11*10^-31kg. If the de Broglie wavelength for an electron in a hydrogen atom is 3.31*10^-10m, how fast is the electron moving relative to the speed of light? The speed of light is 3.00*10^8m/s. Express your answer numerically as a percentage of the...
November 4, 2007

economics
Where does Bexar County rank among texas counties in per capita income? <br><br> Where does Cameron County rank among texas counties in per capita income? <br><br> what was the inflation rate in hungary in 1945-1946?
October 30, 2007

Lunch
take some almonds as a snack throughout the day. As for lunch, take a balanced lunch = with some fruit for dessert, ex.an apple or pear or something of the sort. Main course could be something like a turkey sandwich on whole wheat, or on a whole wheat begal if you so choose. ...
October 29, 2007

CHEM
i mean... 0.574L didn't work.
October 29, 2007

CHEM
Butane, C4H10, is a component of natural gas that is used as fuel for cigarette lighters. The balanced equation of the complete combustion of butane is: 2C4H10(g) + 13O2(g)->8CO2(g) + 10H2O(l) At 1.00atm and 23*C , how many liters of carbon dioxide are formed by the ...
October 29, 2007

CHEM
I worked the info above out &, yes, your thinking was indeed correct. Thank you heeps.
October 28, 2007

CHEM
I tired 7.79g of He added & it told me this: This number looks like the final mass of He multiplied by 2. Instead, find the difference between the final and initial masses.
October 28, 2007

CHEM
A cylinder with a movable piston contains 2.00g of helium, He, at room temperature. More helium was added to the cylinder and the volume was adjusted so that the gas pressure remained the same. How many grams of helium were added to the cylinder if the volume was changed from ...
October 28, 2007

CHEM
well...I managed to use the correct equation: M=mRt/PV...& the answer came to Ar. Thank you very much!!
October 28, 2007

CHEM
the only prob left is: do I just add the variables? or which ones do I take into account? PV=nRT n=RT/PV...or should I be using: M=mRT/PV???
October 28, 2007

CHEM
#2= 1.61atm:)
October 28, 2007

CHEM
ok...I tried my answer...I got the first part correct..it was actually 0.455atm.
October 28, 2007

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