Thursday
July 24, 2014

Posts by K


Total # Posts: 741

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 ...

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.

CHEM
The answer was B

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 amorp...

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

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...

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?

CHEM
yes...I guess they were looking for #3.

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-p...

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:...

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

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!!!

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 ...

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" ...

CHEM
I got the answer correct!!...It was BP-BP < LP-BP < LP-LP

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 th...

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 t...

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

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??

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

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 e...

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 shou...

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 altoget...

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 t...

Art
Is a natural painting also a representational one?

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

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

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, ...

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.)

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!!

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?

**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??

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

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

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 decrea...

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??

CHEM**
ignore the "At"...it was supposed to be "Ar-argon"

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 tha...

**CHEM**
this order came up being correct. Thank you

**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***???? ...

CHEM
the 4th one was correct as well. Thank you!

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-)

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 elem...

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.

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"???...

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.

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 ...

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

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?

CHEM
where am I going wrong?

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

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??

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.

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 wavel...

CHEM
2.0*10^-34 was correct. Thank you.

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?

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 questio...

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

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

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: -...

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 sta...

CHEM
thank you..I reworked it & the answer came to: 0.73%.

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...

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?

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. Y...

CHEM
i mean... 0.574L didn't work.

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 combust...

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

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.

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 ...

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

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???

CHEM
#2= 1.61atm:)

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

CHEM
for Part 1: would the P2 just be 0.454 atm then? I went: P1*V1=P2*V2 then: P2=P1*V1/V2? So...1atm*1L/2.20L = P2= 0.454atm??

CHEM
A) a picture shows a container that is sealed at the top by a movable piston. Inside the container is a ideal gas at 1.00atm , 20.0 *C, and 1.00L. (The pic is of a 2L container which has a piston pushed downward to the 1L level. Under the piston, under the 1L mark, is a sample...

CHEM
thank you!

CHEM
Thank you muchly!! (the questions are just from an old MT that we were to go over to study for the real MT this coming Sat.)

CHEM
so for #14 I got: 4mols #16: 1.0mL #17...the other two choices were b-0.1MCH3COOH & then d) both A&B, that's why I didn't bother putting them in, considering b is not an electrolyte. #25: b- HCl? #2, about Av's #...the options were: a)the # of Hydrogen atom in exac...

CHEM
I was just wondering if someone would be able to critique my answers for the following Chem questions? they range from pretty basic to a bit more... 2)which of the following is the definition of the value of Avogadro's constant: b) the # of Carbon atoms in exactly 12g of c...

Science
What would be the likely function of a plant cell containing many chloroplasts?

CHEM
Help on part "c": The forensic technician at a crime scene has just prepared a luminol stock solution by adding 19.0g of luminol into a total volume of 75.0mL of H2O. a)What is the molarity of the stock solution of luminol? answer I got: molarity of luminol solution ...

CHEM
this answer, 83.9mL worked...thank you for the guidance.

CHEM
Help on part "c": The forensic technician at a crime scene has just prepared a luminol stock solution by adding 19.0g of luminol into a total volume of 75.0mL of H2O. a)What is the molarity of the stock solution of luminol? anwer I got: molarity of luminol solution =...

CHEM-last part prob.
(oh...slightly dislexic...yes...I meant 0.225 moles, that would have helped if I had noticed before & typed it in correctly.)

CHEM-last part prob.
ok...so I shouldn't have multiplied through by 2. That makes a lot more sense. Thank you, yet again, and it came out alright.

CHEM-last part prob.
I tried this answer & it was incorrect.

CHEM-last part prob.
Aluminum reacts with chlorine gas to form aluminum chloride via the following reaction: 2Al(s) + 3Cl2(g) -> 2AlCl3(s) You are given 19.0g of aluminum and 24.0g of chlorine gas. a)If you had excess chlorine, how many moles of of aluminum chloride could be produced from 19.0g...

CHEM
I kept trying it, via comparing it to a, & finally did come up with 0.255mol AlCl3...I had just gotten the question incorrect,somehow, 4x...so I had to ask. Thank you for your patience with me. I will be looking into getting a tutor shortly.

CHEM
Aluminum reacts with chlorine gas to form aluminum chloride via the following reaction: 2Al(s) + 3Cl2(g) -> 2AlCl3(s) You are given 19.0g of aluminum and 24.0g of chlorine gas. a)If you had excess chlorine, how many moles of of aluminum chloride could be produced from 19.0g...

CHEM
it worked out beautifully. Thank you!

CHEM
My balanced equation is: a) 2C8H18(g) + 25O2(g) -> 16CO2(g) + 18H2O(g) b) 0.290 mol of octane is allowed to react with 0.670mol of oxygen. Which is the limiting reactant? (((Which I found Oxygen to be the limiting reactant.))) I do not understant how to work out "c&quo...

Math - Algebra
bg

CHEM
THIS time I got it correct! answer = 5.13x10^-19 molecules! THANK YOU soooo much!! I only had 2 attempts remaining!

CHEM
How many molecules of ammonia are produced from: 2.58x10^-4g of Hydrogen? My balanced equation: 3H2 + N2 = 2NH3 I worked this question as: mol of H = 2.58x10^-4g/1.00794g/mol= 2.559676x10^-4 mol mol of NH3 produced = 2x2.559676x10^-4mol/3mol NH3 = 1.706450701x10^-4 Molecules =...

CHEM
Calculate the mass (in grams) of the product formed when 10.1g of the underlined reactant completely reacts. Assume that there is more than enough of the other reactant. 2K(s) + __Cl2(g)__ -> 2KCl(s) I cannot get the correct answer.

CHEM
A scientist wants to make a solution of tribasic sodium phosphate,Na3PO4 , for a laboratory experiment. How many grams of Na3PO4 will be needed to produce 575mL of a solution that has a concentration of Na^+ ions of 1.40 M? Answer: mass of Na3PO4 = _____ How is this question s...

CHEM
My question doesn't have to be answered. I figured out what they were asking and got it correct.

CHEM
For the reaction shown, find the limiting reactant for each of the following initial amounts of reactants. 4Al(s) + 3O2(g) -> 2Al2O3(s) 4mol Al, 2.6mol O2? a) 4mol Al, b) 2.6mol O2. I seriously have no idea what they are asking! What do you do with the 4mol Al & 2.6mol O2.....

CHEM
does this sound correct? 8.00X10^-4 kg?

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