Number of results: 13,384
Chem
thanks drbob22, much better explanation!
Friday, October 14, 2011 at 9:16pm by Anonymous
Drbob22
Trust me Drbob22 if I would have known the answer I wouldn't have posted the question. That's obvious!
Tuesday, October 9, 2007 at 5:12pm by Anonymous
chem/thank you DrBob22
thank you so much....your good, I wish you be my teacher I be passing my class with no problem....
Thursday, December 16, 2010 at 11:58am by julia
chem class
If necessary, you CAN calculate the pH at the neutral point. HOH ==> H^+ + OH^- Kw = (H^+)(OH^-) = 1 x 10^-14 (H^+) = (OH^-); therefore, (H^+)^2 = 1 x 10^-14 and (H^+) = 1 x 10^-7 M pH = -log(H^+) = 7.0
Wednesday, November 24, 2010 at 10:22am by DrBob22
science(chem)
I have typed a response twice but the board won't let me post it. I don't know the trouble. I'll try this last time. When I say my tutors I mean those tutors who post on this board, and other boards. I read almost all of them and I learn something new every day.
Monday, May 5, 2008 at 12:14am by DrBob22
chem /Sue
I'm sorry...I'm not using his name..I know his one of the best tutors, his help me a lot in understanding chemistry..I wrote like that so he could read my question..and check my work...sorry Ms. Sue...all i was trying to do is to direct the question for Drbob22...sorry...
Monday, November 15, 2010 at 5:49pm by julia-Drboob22
chemistry
DrBob22 PLEASE hELP!!!!!!!!!!!!!!!!!
Monday, March 12, 2012 at 4:43pm by jenny
chemistry
answered elsewhere.
Sunday, May 4, 2008 at 11:59pm by DrBob22
DrBob22
I think I partially answered that.
Wednesday, April 29, 2009 at 10:56pm by DrBob222
chemistry
WTH did DrBob22 just say?
Tuesday, October 19, 2010 at 11:48am by dina
Dr. Bob Chemistry question
Answered below.
Monday, May 5, 2008 at 11:49am by DrBob22
To DrBob22
are we supposed 2 divide something after we solve the equation
Thursday, May 3, 2012 at 7:51pm by Candy
Chemistry
to DrBob22 .... what volume fo water would u use?
Friday, October 22, 2010 at 9:15am by Sam
DrBob22
Can you check my answer in the last boiling point topic I posted? Thanks.
Wednesday, April 29, 2009 at 10:56pm by Chopsticks
chemistry
Yes, alkyl halides are made from alkanes (at least they are sometimes).
Monday, May 5, 2008 at 1:00am by DrBob22
science
Electron dot structures are difficult, if not impossible, to draw on these boards.
Monday, May 5, 2008 at 12:05am by DrBob22
Chemistry
A Bunsen burner, if hooked to a gas supply, is a device for heating materials.
Wednesday, November 24, 2010 at 11:26am by DrBob22
science
I would not expect a compound to be formed between Cr and element number 27 (Cobalt).
Monday, May 5, 2008 at 12:02am by DrBob22
science year 7
Zinc chloride is a white solid which is soluble in the aqueous solution present in HCl.
Monday, May 5, 2008 at 8:54am by DrBob22
chemistry
What's the problem in doing this? I should be easy enough. Tell me your trouble; perhaps I can figure out the mental block.
Thursday, March 10, 2011 at 11:43am by DrBob22
DrBob22
We have never learned the formula (P1V1/T1) = (P2V2/T2) Is that the same thing as P1V1T2=P2V2T1 ??
Wednesday, March 25, 2009 at 12:48am by Chopsticks
chemistry
I would call chloroethane an alkyl chloride. If alkanes are defined as hydrocarbons, and this compound also has Cl, then it is not an alkane.
Monday, May 5, 2008 at 1:00am by DrBob22
Science
What role does the sun play in the formation of tides? I read the article that you posted DrBob22, but I want it in short terms, and am unable to put it in them, please help.
Wednesday, February 10, 2010 at 10:24pm by Sara
Physical Science [DRBOB22 PLEASE CHECK]
Btw Dr.Bob, the answer to #3 is actually D, what I drwls and I said. Just letting you know ;) -MC
Saturday, May 9, 2009 at 11:17am by mysterychicken
Chemistry
I believe amides hydrolyze to the acid and NH3 CH3CH2COOH + NH3
Wednesday, November 24, 2010 at 1:46pm by DrBob22
chemistry
(atomic mass O/molar mass C8H8O)*100 = ??
Thursday, March 10, 2011 at 11:45am by DrBob22
Critical thinking
Ag2SO4 is silver sulfate LiF is lithium fluoride CS2 is carbon disulfide CaO is calcium oxide I2 is iodine
Monday, May 5, 2008 at 12:51am by DrBob22
chem/DrBob22
consider the following balance chemical equation: 2NH3(g)+3CuO(s)=N2(g)+3Cu(s)+3H2O(g) if 18.1grams of ammonia reacts with 90.4 grams of copper(II) oxide, which is the limitting reagent?? what is the theorectical yield of nitrogen gasd? if 8.52 g of N2 are formed, what is the...
Monday, November 15, 2010 at 6:23pm by julia
Chemistry
You must have a table in your text or in your lab manual that gives the solubility of some of the salts at various temperatures. . I assume this is an experiment you are conducting. KCl is rather soluble.
Monday, May 5, 2008 at 12:31pm by DrBob22
DRBOB22 I REPLIED TO THE OTHER QUESTION!!
Responded to the original post and follow up at original site. If you have trouble finding it I can come back and paste the asnwer here. !
Wednesday, November 1, 2006 at 4:17pm by DrBob222
Drbob22
I'm sure you are correct. But instead of just giving you the answer, which I'm sure you don't want us to do, tell us what your trouble is so we can help you understand it.
Tuesday, October 9, 2007 at 5:12pm by DrBob222
science
Both are isoelectronic with Ne; i.e., their outside shells are filled with eight electrons and all have the same number of electrons (that is the isoelectronic part).
Monday, May 5, 2008 at 12:04am by DrBob22
Repost Chemistry for GK
This is the lab (determination of gas constant) I provided the link in the previous post. I'm not sure if you used the volume I obtain. Can you explain to me how to find the molar volume? Is what I did correct or is what DrBob22 did corect? Thanks!
Friday, July 11, 2008 at 12:11pm by Anonymous
math
@ Ms. Sue, Thank you for your answer. @ Drbob22, Thank you for your thoughts. The question was produced by my instructor and I'm sure your right, it probably isn't the best question. I have typed it as it was written.
Sunday, December 27, 2009 at 4:13pm by Kay Kay
science
delta Hrxn = (sum delta H products)-(sum delta H reactants). Look these values up in a set of tables (one probably is in your text), substitute and solve.
Wednesday, November 24, 2010 at 4:36pm by DrBob22
Chemistry
Sorry, it should read 10L, not 100L and 9L not 99L. Also, DrBob22 is right you can boil/distill 50mL of water, but only if they do not have the same boiling point, but the answer is to add 9L not 10L.
Thursday, January 17, 2013 at 9:17pm by Devron
Chemistry
DrBob22 please help with the pH. I am not sure if I would use pKa=-logKa=-log(1.9*^-5)=4.74 or do I use [H3O]= 10^-pH =.0040=10*^-ph
Sunday, March 25, 2012 at 12:30pm by Mary
Chemistry
You can't draw a graph on these boards but if its a table, can you either describe it or list the columns and temperatures? You can't type information on this board in columns but you can do it this way, using periods for spaces T........mass KCl/100 mL 10........a ...
Monday, May 5, 2008 at 12:31pm by DrBob22
science
There isn't enough information to write the formulas for any of the compounds formed.QX and QZ is the best I can do; however, we don't know the valencies so we don't know how many of the Q adds to X or Z. We could write QaXb or QcZd where a,b,c, and d are small ...
Monday, May 5, 2008 at 12:01am by DrBob22
chemistry
Use the Ka expression (or the Henderson-Hasselbalch expression). Ka = (H^+)(CH3COO^-)/(CH3COOH) You are given CH3COO^- and CH3COOH, solve for H^+, then convert to pH.
Wednesday, November 24, 2010 at 10:22am by DrBob22
chemistry
drbob22 I think the reason you are getting a negative number instead of the positive you need to find the log is because you put your A and B in the places. Try inverting them. I'm sure you will get a positive. I followed your instructions to a Tee and never came up with a...
Monday, February 4, 2008 at 8:54pm by Shameca
AP Chem
I looked at the first four, they are right. Dont you work with someone on chem homework? Like a study group? That is a very effective way to work chem and physics problems.
Wednesday, November 19, 2008 at 11:22am by bobpursley
algebra
Actually, DrBob22, I disagree. neither The second choice is almost correct. It is missing a minus sign. It should be: 9b^2-16b^2 Why? (-4)^2 (b)^2 => 16b^2 remember, you're square both the coefficient and the variable. note: the minus sign is not in the parenthesis...
Monday, July 14, 2008 at 10:22pm by Anonymous
chemistry
You didn't convert to moles correctly. The molar mass of O2 is 22.4 L/mole ONLY at STP and 25C is not STP. Use PV = nRT, solve for n, then n/1L = M and I get 0.00126M. (Note: IF you could use 22.4, you should have divided 0.0309/22.4 = 0.00138 but that would be at 273K (...
Wednesday, August 31, 2011 at 11:20am by DrBob22
science
NaOH + HCl ==> NaCl + HOH strong base + strong acid. Determine mols NaOH = M x L = ?? Determine mols HCl = M x L = ?? Determine which reactant is in excess, then calculate molarity NaOH or HCl and pH from that. Post your work if you get stuck.
Monday, May 5, 2008 at 3:23am by DrBob22
Dr. Bob Chemistry question
Divide all the numbers by the smallest number, in this case that is 0.2068. Then round to the nearest whole number. If you have one that will round to 1/2, then multiply all by 2 to get rid of the 1/2. If you still don't get it, post your values for the division along with...
Monday, May 5, 2008 at 11:49am by DrBob22
Chemistry
Generally speaking, write an extended summary, in which you focus on the conclusions you can draw from the experiment you performed. Some disciplines write an experimental, then discussion, then conclusions. I like to write the discussion and conclusion together. That way I ...
Sunday, May 4, 2008 at 10:48pm by DrBob22
Dr. Bob Chemistry question
No, you're done, except for multiplying everything by 2 to get rid of the 1/2 in 5.5 So you have H2O = 5.5 x 2 = 11 C2O4 = 3 x 2 = 6 Fe^+3= 1 x 2 = 2 K^+ = 4 So you have K4Fe(C2O4)6*11H2O I don't know what it is but something is wrong here BECAUSE Fe is NOT +3 in this ...
Monday, May 5, 2008 at 11:49am by DrBob22
Chemistry
A latex balloon, wall thickness 3.091 x 10-4 m, contains helium at a concentration of 0.43 kg m-3. Under these conditions the total surface area of the balloon is 0.68 m2. The diffusion coefficient of He in latex at room temperature is 4.9 x 10-9 m2s-1. Calculate the rate of ...
Saturday, December 15, 2012 at 10:33pm by Stud
chemistry
5% NaCl w/v means 5 g NaCl/100 mL soln. So for 250 mL soln you will need 5g x (250/100) = ?? You can look at it another way. (grams/mL)*100 = % (X/250)*100 = 5 Solve for X.
Thursday, March 10, 2011 at 11:45am by DrBob22
Chemistry
Is the solubility of KCl then 46 grams/100 mL at 70 degrees C? (I don't know if that is the unit for you OR if you were just copying the unit I gave as an example.) If 46 g/100 mL, then g in 50 mL = 46 x (50 mL/100 mL) = 23 g/100 mL.
Monday, May 5, 2008 at 12:31pm by DrBob22
chem help
ok thanks alot... the PartB asks for: What is the percent ionization of ammonia at this concentration?
Saturday, February 28, 2009 at 11:56pm by chem
chem
I DONT GET WHATS DONE.. DR.Bob22 - could u please explain this again..thank u
Tuesday, February 17, 2009 at 12:10am by CHEM
gen chem
i tried that, apparently its not the right answer either =/.
Saturday, May 8, 2010 at 7:46pm by Chem
CHEM organic chem
Responded above to a later repost.
Tuesday, November 13, 2007 at 6:18pm by DrBob222
Chem
0.102 x 0.0821 x 273 / 1.0 what can i express this in the correct number of significant figures ?@_@
Wednesday, August 29, 2012 at 4:51am by Chem ):
chem
... This isn't in the right section. That's math, not chem. the answer though is, 23.
Wednesday, February 10, 2010 at 7:40pm by Nadia Samim
O.CHEM -> PLEASE CHECK!!
Thank you...good to know, but isn't there a "Dr.Russ" that works with Organic Chem??
Wednesday, March 12, 2008 at 9:48pm by K
G-chem/org. chem=>Dr. Bob222
I mean are setups differ for part 1
Friday, February 8, 2013 at 5:58pm by Devron
chem
The answer on mast chem is 279 if you have 230 grams instead of 200.
Monday, February 15, 2010 at 4:46pm by Anonymous
Chem
maybe try using P1V1/n1T1 = P2V2/n2T2 ... im in chem too...
Saturday, February 27, 2010 at 1:16am by fellow student
chem
sorry read it wrong, doing this now in chem
Tuesday, March 19, 2013 at 6:02pm by Amanda
chem
How to find the %(W/V) of 134mL of a 0.610 M solution of Mg(OH)2
Thursday, February 16, 2012 at 9:00pm by chem
organic chem
cadaverine is AKA pentane-1,5-diamine
Tuesday, April 26, 2011 at 5:18am by chem
organic chem
cadaverine is AKA pentane-1,5-diamine
Tuesday, April 26, 2011 at 5:18am by chem
gen chem
yes, I figured that one out. Thanks so much for the help!
Sunday, May 9, 2010 at 3:42pm by Chem
chem help
sorry the 2nd question is the right one
Saturday, February 28, 2009 at 11:56pm by chem
chem PLEASE HELP
I am very sorry. Chem is just not my thing and i looked in my notes the book and everything
Thursday, April 14, 2011 at 7:40pm by Sal
chemistry
KOH is a strong base in aqueous solution; therefore, the (KOH) = (OH%-). For pH = 11.53, use pH + pOH = pKw = 14 to solve for pOH, then from pOH = -log (OH^-), solve for OH^-. That will give you the molarity of the KOH you want for that pH. Then M = moles/L. Substitute L and ...
Wednesday, November 24, 2010 at 5:26pm by DrBob22
chem
ahh i hate chemisty, i'm kindof slow too and everything confuses me in chem.!! i feel the same way as you:)
Thursday, May 29, 2008 at 9:59pm by bethany
CHEM
FUUUUKKKK CHEM
Monday, November 5, 2007 at 10:14pm by ABU EL 3BED
chem
Sarah, 4.70 is what you get when you do the -log (Ka)
Monday, April 4, 2011 at 1:24am by chem
Chemistry
so the first one is wrong too hmmm ! yeah ur reasoning makes sense ... i will ask my chem teacher too
Saturday, November 28, 2009 at 8:14pm by Chem Lover
Chem
1. 7.95 g 2. 7.956 g 3. 7.96 g 4. 7.960 g 5. 8.0 g 6. 8.00 7. none of the above Which is more the right choice....It can't be 7,6,5 for sure....But I thought it was 3. It's not 2.
Friday, February 8, 2008 at 3:13pm by Chem Help!!
gen chem
what must be the current in amperes to plate out 7.437g of Al from am aqueous solution of Al3+ in 5.4x10^2 minutes?
Saturday, May 8, 2010 at 6:56pm by Chem
G-chem/org. chem=>Dr. Bob222
I just looked at Dr. Bob222's post for when you initially posted this question and the setup that I gave you for part 1 differs from the setup that he gave you for part 2. I will let him resolve that for you since he has more experience in G-chem then I do, and he is ...
Friday, February 8, 2013 at 5:58pm by Devron
gen chem
that works! thank you so much!!
Sunday, May 9, 2010 at 3:42pm by Chem
gen chem
yes, it wants an actual value
Sunday, May 9, 2010 at 3:17pm by Chem
gen chem
what is "n" and thank you so much for all the help!
Saturday, May 8, 2010 at 7:46pm by Chem
Chem
The correction terms in the Van der Waals equation for a gas are designed to correct A. the pressure term (P +a/V2) for the attractive forces between particles. B. the volume term (V-b) for the finite volume of the particles. C. For the volume term (b) not the pressure term (a...
Wednesday, October 18, 2006 at 7:23pm by Mendi
DrBob22
Suppose that 120.mL of argon is collected over water at 25C and 780.0 torr. Compute the volume of the dry argon at STP. Would this be involved with Charles law? DrBob11: (P1V1/T1) = (P2V2/T2) Don't forget to use T in Kelvin. Subtract the vapor pressure of water from the ...
Wednesday, March 25, 2009 at 12:48am by Chopsticks
chem help
see the short paragraph and visual titled Predicting ion charges. http://antoine.frostburg.edu/chem/senese/101/atoms/
Saturday, November 24, 2007 at 7:59pm by bobpursley
DrBob22
Sure. (P1V1/T1) = (P2V2/T2) = P1V1T2 = P2V2T2. That's the general gas law. It becomes Boyle's Law if you keep T constant (just cover up T1 and T2 and you're left with P1V1=P2V2). Or it becomes Charle's Law if P is constant (cover up P1 and P2 and it becomes ...
Wednesday, March 25, 2009 at 12:48am by DrBob222
gen chem
2NO <-> N2 O2 initial .116 0 0 change -x +x +x equil .116-x x x
Sunday, May 9, 2010 at 3:42pm by Chem
Intergated chemistry/physics
time=distance/velocity. This is a very odd question for "integerated" chem/physics. Where is the chem?
Wednesday, October 3, 2012 at 1:53pm by bobpursley
gen chem
yes I did, but im still not getting the right answer. I got .1136 which is not the correct answer.
Sunday, May 9, 2010 at 3:42pm by Chem
chem help
Ammonia,is a weak base with a Kb value of 1.8x10^-5 .What is the pH of a 0.22M ammonia solution?
Saturday, February 28, 2009 at 11:56pm by chem
chem help
Ammonia,is a weak base with a Ka value of 1.8x10^-5 .What is the pH of a 0.22M ammonia solution?
Saturday, February 28, 2009 at 11:56pm by chem
chem: study of kinetics
he gave us an example of what the slope might be in class and it was -1.3x10^2 but my slop is completely different, was i supposed to do calculations? or just get the one from excel? what do i put in the 2 blanks?
Saturday, October 16, 2010 at 2:20pm by chem
ap chemistry
I agree on the tutor. Also, get another text (college used book store) to see the same material in differing words. On the ap chem board exam, nationally, most do not do well. I have to be honest, most ap chem students need to retake college chem if for nothing else, the lab ...
Sunday, November 4, 2012 at 4:07pm by bobpursley
gen chem
what would Qc be if the pressure of the container decreased by a factor of 2.417 for the following reaction? 4Hcl(g)+O2(g)<-->2Cl2(g)+2H2O(g) Kc=13.298 @ 753K
Sunday, May 9, 2010 at 3:17pm by Chem
In your opinion=> has it payed off for you Dr.Bob? (I need some advice)
I don't know where to start but I was thinking of changing my major to chemistry but that would require me to go to another school since mine doesn't have a chemistry major. This is rather ironic since they have all the major chem classes needed to get a chemistry ...
Tuesday, March 25, 2008 at 9:50pm by ~christina~
chem
The larger an atom the farther the electrons are away from the nucleus; therefore, the easier it is to distort them. Here is a site that talks about that. http://www.chem.purdue.edu/gchelp/liquids/disperse.html
Friday, November 28, 2008 at 4:49pm by DrBob222
chem
You have to subtract the water vapor pressure at 25C from 760Torr. http://intro.chem.okstate.edu/1515sp01/database/vpwater.html
Tuesday, February 2, 2010 at 10:41pm by bobpursley
physics vs. Chem
Doesnt physics seem to be harder than chem? Anyone?
Sunday, October 24, 2010 at 2:28pm by Kavi
gen chem
E cell is not given, just the E0 cell which is -1.133V
Saturday, May 8, 2010 at 7:46pm by Chem
chem- drbob222 please help
my original question was: how do i figure this out?? How much heat does your body lose when 2.46 g of sweat evaporates from your skin at 25°C? chem - DrBob222, Tuesday, February 22, 2011 at 10:52pm q = mass water x delta Hvaporization. chem - Rebekah, Wednesday, February ...
Wednesday, February 23, 2011 at 5:49pm by Rebekah
Chemistry
I'm lost!!! Not sure if I'm just losing concentration after 50 chem problems or losing my mind with 3 kids running around still and a chem exam at 8am!!!
Friday, March 29, 2013 at 12:15am by Ryan Curry
Chem 2
Sorry my friend Barbie and I are doing are chem h.w. together. We each posted a question and since were using the same computer the last name always stays saved in the page...sorry I forgot to change it. It
Wednesday, February 27, 2008 at 3:28pm by Amanda
Chem
What causes dispersion forces? Disperson forces are caused by an unsymettrical distribution of charge in the molecule, causing a net electric force. http://www.chem.purdue.edu/gchelp/liquids/disperse.html
Tuesday, January 9, 2007 at 6:46am by Dennis
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