March 26, 2017

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Number of results: 467

Where did you get 5E-5. Is this how you set it up? 0.01 x 0.05 = 5E-4 If so, is it supposed to be 5E-4 instead of 5E-5? What is the equilibrium constant for a weak acid HA that dissociates 1% at an initial concentration of 0.05 M according to the following balanced chemical ...
March 14, 2016 by Nevaeh

DrBob222 I am kind of stuck with the balancing stuff, and I already had send the post, did you not read it?
July 15, 2010 by Derrick

Where is DrBob222?
Hey does anyone know when DrBob222 comes on here, cause I have a lot of chemistry questions which I need him to check. Thanks.
October 11, 2010 by Anonymous

math 4thgrade thanks DrBob222
Thanks a lot I get it now!!!!!! From Adam To DrBob222
November 15, 2006 by Adam

To DrBob222
DrBob222 do you know anything about Heredity and Punnet Squares?
June 9, 2010 by Sara

Chemistry to DrBob222
DrBob222 You are an amazing person! I have received more help from you the past two days that I have this whole semester from my instructor! You have an amazing gift of breaking things down to understand completely! Where are you from? Do you get paid for this somehow? look me...
February 26, 2015 by Jennie

DrBob222 please check
DrBob222 please check my physics question posted at 8:55pm. The subject is drwl please check. I am not getting a response from drwl. Thanks! Mary DrWLS is not on right now. My physics is too poor to trust my answers. Bob Pursley is smarter than I am; he does physics, math, and...
February 27, 2007 by Mary

Drbob222, even if you just tell me that there is an answer to the following problem then i know that there is an answer because i've tried many ways and i can't get x alone. -4(2x-3) = -8x +5 Is there an actual answer for this one? No. There is no answer, the question is ...
December 19, 2006 by jasmine20

solve Ka for HX => H^+ + X^- given 0.1M LiX at pH=8.9 Chemistry - DrBob222, Tuesday, March 30, 2010 at 6:32pm LiX(aq) ==> Li^+(aq) + X^-(aq) X^- is a base and hydrolyzes in water to X^- + HOH ==> HX + OH^- Make an ICE chart and substitute into the following: Kb = (Kw/...
March 30, 2010 by Larry

I'm sorry the problems i posted had a couple of errors how i posted it here they are: Posted by DrBob222 on Friday, November 24, 2006 at 6:19pm in response to Math. Thanks for showing your work. It helps us to know where you are having trouble. #4. [25/ (2^3-3)]*2 the star two...
November 25, 2006 by Jasmine20

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 23, ...
February 23, 2011 by Rebekah

I got an answer of -1.34 x 10^3 KJ/mol. A 10.00 mL aliquot of 0.100 M NaOH is added to 15.00 mL of 0.100M HCl in a coffee cup calorimeter. The initial temperature of the two dilute liquids were both 25.0 degrees C and the final temperature of the mixture was found to be 37.8 ...
March 14, 2016 by Nevaeh

solve Ka for HX => H^+ + X^- given 0.1M LiX at pH=8.9 Chemistry - DrBob222, Tuesday, March 30, 2010 at 6:32pm LiX(aq) ==> Li^+(aq) + X^-(aq) Question for DrBob222 - is the X^- value in the ICE calculations 0.1 from the initial LiX 0.1M? X^- is a base and hydrolyzes in ...
March 30, 2010 by Larry

Chemistry(Please respond)
Calculate the pH of an aqueous solution of 0.15 M potassium carbonate. I know that pH = -log(H30+) but I am not sure how to start this problem. Chemistry(Please help) - DrBob222, Saturday, April 14, 2012 at 11:09pm Hydrolyze the CO3^2-. CO3^- + HOH ==> HCO3^- + OH^- Do an ...
April 18, 2012 by Hannah

DrBob222, I don't know how to solve this problem either. And yes, this is the question for this problem. I even double check it. Please help. Chloroform (CHCL3) has a normal boiling point of 61 'C and an enthalpy of vaporization of 29.24 kJ/mol. What is the value of delta Gvap...
April 30, 2013 by Chloe

so i posted this question yesturday and got some help. which is the stuff below. can you look at the last thing i said which was the answer i got by doing what DrBob222 said to do and tell me if its correct.(the question is the first section) thanks chem - hannah, A salt ...
November 10, 2010 by hannah

Thank You!
February 5, 2008 by alan

Strychnine, C21H22N2)2(aq) is a weak base but a powerful poison. Calculate the pH of a 0.001 mol/L solution of strychnine. The Kb of strychnine is 1.0 x 10^-6 DrBob222, I am planning on obtaining a pHD in about nine years:P Can you give me some advice on how to be that 1% of ...
April 6, 2008 by Sarah

To DrBob222
What is 14/4 as an integer?
September 22, 2009 by Shavaleir

DrBob222, am i correct
is the answer 64.48$
July 1, 2009 by scooby9132002

to drbob222
thank you so very much
March 26, 2012 by Celest

To Drbob222
Please help me on my question thanks
May 12, 2014 by Durga

If you don't mind me asking, How are you so smart, and how old are you?
April 7, 2010 by Courtney

To Drbob222
I don't get how to get N, please show me cause I don't understand
April 21, 2014 by Jannet

What is the formula for 2-bromomethylpropane ?
October 14, 2014 by Tim

Thank you very much. I appreciate it a lot.
March 28, 2008 by Leigh

THANKS so much for all of your quick and useful help!
July 16, 2009 by paul

thankyou for your help its helped are a star!
October 6, 2009 by dominique

Drbob222 that does not help. got anything else up ur sleeve?
December 13, 2009 by yppum

Honors Chemistry
I got 206.67 g Fe, DrBob222
February 23, 2010 by Ana

To Drbob222
Please check my post again
April 21, 2014 by Jannet

Chemistry(Please help, thank you)
I have to calculate the concentration of I2 produced (# of moles of I2 produced / L) based on the stoichiometric ratio in the following equation. 2S2O3^2- + I2 -> 2I^- + S4O6^2- Chemistry(Urgent, please help) - DrBob222, Sunday, February 26, 2012 at 9:47pm If you know the ...
February 27, 2012 by Hannah

Chemistry/ Dr.Bob222
DrBob222 I am beginning to understand about balancing equations well, thanks to your help, but there are still some other things, which I am having a hard time figuring out. Complete and balance the following chemical reactions between an acid and a metal. A) HBR + Mg -> ...
July 13, 2010 by Derrick

If a wave has a period of .02 seconds and a speed of 4 m/s, what is its wavelength? .08 m
April 5, 2008 by Jon

I reponded back to you on my science helpers post.
April 6, 2010 by Sara

DrBob222 - it says my answer should be a number.
October 20, 2013 by Morgan

ap chemistry
What is the [H3O+] of a solution with [OH-] = 6.3 × 10-4 M? A. 6.3 × 10-18 M B. 10.80 M C. 6.3 × 10-4 M D. 1.6 × 10-11 M DrBob222 can you help me with this question please?
September 14, 2016 by jessica

Convert a pressure of 23.8 in. Hg into kilopascal. Ok so I looked up kilopascal and it Said 1 Kpa = 1000 pa So I began to set it up like this 23.8 / 29.2 x1000 am I correct Chemistry - DrBob222, Thursday, October 13, 2011 at 1:48pm I don't think that will get it. I would go ...
October 13, 2011 by Monique

Is the answer for part c 0.91? A 1.0 L ball containing Ar at 5 atm is connected to a 10.0 L ball containing N2 at 2atm. A)Calculate the partial pressures and mole fractions of Ar and N2 after the valve is opened and the gases are allowed to mix (they fill the balls on both ...
March 14, 2016 by Nevaeh

The Doppler effect is a change in the ______of a sound. pitch
April 5, 2008 by Jon

Are you done helping me? Sorry, to bugg you i just reall need the help.
April 6, 2010 by Courtney

Thanx DrBob222
Thank you sir for helping me out with those chemistry problems.
July 11, 2010 by Derrick

Can you please help me with some questions I have on my Chemistry lab?
November 27, 2010 by Mandy

chem please help drbob222
When is there a need to determine G? A. When H > 0 and S = 0 B. When H > 0 and S > 0 C. When H = 0 and S < 0 D. When H > 0 and S < 0 P.S. there are triangles before the G, H, and S.
November 25, 2014 by Morgan

for Drbob222
how do I calculate pressure exerted by H2 in a Mg and HCl reaction? (weighing by redox)
October 29, 2007 by Rebecca

DrBob222 please help me answer the question that I posted pleaseee, pleaseeee
February 16, 2010 by Jennifer

Is DrBob222 available tonight? Please let me know, I need some chem help.
October 11, 2010 by Karen

DrBob222- Is STP = to 273K? If so, would i use P1V1/T1 = P2V2/T2??
February 15, 2012 by Daddy

Chemistry (DrBob222)
Is the relationship between delta G and Temperature inverse or direct?
December 4, 2013 by K

Chemistry (DrBob222)
Hi Dr. Bob would you please tell me what D rpresents? Thank you! What is the reactant, products, and what compounds is it? Is it H2O, O2, or what? What are the transition molecules? Help please. Do as below to get to the image. I couldn't put the URL in and it isn't my website...
June 17, 2012 by Anonymous

Drbob222, math , algebra
Sorry , I thought it went through. What i want to be corrected is the following. (30)
December 18, 2006 by jasmine20

I so need help please tell me some obscure facts about spain
December 7, 2007 by Lauren F

To DrBob222
can you please have a moment to look at my other previous posts, thanks a lot:-)
May 3, 2010 by Sara

July 14, 2010 by Sam

to DrBob222 wouldn't it be like this then 4.86L/12.75kg*1000cm^3/1L*(1kg/1000g)^3
August 26, 2010 by maryanne

to drbob222 ok, the pka (hclo) = 7.54 the ph = 7.35 this problem was under "preparing a buffer" section
March 6, 2011 by sam

DrBob222 No. 0.30 isn't the correct answer either. I'm going to ask my prof about it tomorrow.
March 4, 2012 by Kiana

What happens when a wave reaches the boundary of a new media? it would reflect back.
April 5, 2008 by Jon

For incomplete cancellation to occur, opposite pulses must have. equal displacements
April 5, 2008 by Jon

As a sound source moves away from a stationary observer, the number of waves will. decrease
April 5, 2008 by Jon

DrBob222 - for molar mass do you use significant figures? If so would the answer be 0.05 (3.55/65.39)3.55 has 3 SF's correct?
April 18, 2010 by Tracey

college chemistry
DrBob222. when you move ice from zero to final T. Do you add 100 cal.?
January 30, 2014 by Linda

Hey DrBoB222 I was wondering if you could help me with that problem just a little bit ago again?
March 14, 2015 by jack

I know I posted this but you didn't answer! Please help!!!! Consider the following reaction at 298 K: C(graphite) +2Cl2 (g) -----> CCl4(l) Calculate the following quantities. Delta H: -139 kJ/mol deltaS(sys)=? J/mol*K deltaS(surr)=? J/mol*K deltaS(univ)=? J/mol*K My answer ...
March 15, 2012 by Kelsey

The following thermodynamic data was obtained for an unknown compound. Delta Hvap = 31.3 kj/mol and Delta S Vap= 79.7 kj/mol .Calculate the normal boiling point of this compound in Celcius.. Thank you! Chemistry - DrBob222, Tuesday, April 30, 2013 at 12:31am dG = dHvap - ...
April 30, 2013 by Chloe

I really want to know what this symbol means ^. I haven't learned about it at all. Does it mean squared or something?
April 20, 2010 by Sara

to drbob222: the book says that the naclo grams are equal to 2.4. how did they come up with that from the Henderson hesselbalch equation?
March 6, 2011 by sam

For the medium to remain undisturbed as two pulses pass the same point, they must have. different amplitudes
April 5, 2008 by Jon

what does air pressute do to the freezing, melting ad boiling point *Note to DrBob222: If you are going to answer this, please , no links
September 17, 2009 by Chad

To DrBob222(Please check Chem)
(This homework question has been removed due to a copyright claim submitted by K12 Inc.)
June 21, 2012 by Liz

Can you check my previous postage I'd reply already. Thank you done below What are about the other messages are they okay too. I think I just finished with all of them.
December 11, 2006 by Jasmine20

You just answered my previous half-life question, and I was curious how to find the value of k. You said that k = 0.693/t1/2 , but how do you evaluate t sub1/2?
April 12, 2011 by Sarah

chem please help drbob222
Why is it important in gravimetric analysis to add an excess amount of precipitating ions to a solution containing an analyte
December 2, 2014 by Morgan

Chemistry- DrBob222
What is the equilibrium constant for a weak acid HA that dissociates 1% at an initial concentration of 0.05 M according to the following balanced chemical equation? HA <----> H+ + A-
March 12, 2016 by Nevaeh

Calculate the standard free-energy change for the following reaction at 25 C degrees. 2Au^3+(aq)+3Ni(s) <-- --> 2Au(s)+3Ni^2+(aq) Ni2+(aq) + 2e- -> Ni(s) E=-0.26 Au3+(aq) + 3e- -> Au(s) E=+1.498 G= ? KJ Would it be G=1.758? •Chemistry - DrBob222, Sunday, March 31...
April 1, 2013 by Anon

chemistry (DrBob222)
A student fails to fill the cuvette 2/3 full with the reaction mixture ( CV+ and OH-). What effect does this error have on the measured absorbance values? Thank you :)
October 9, 2013 by K

DrBob222 - can you set up the equation for the volume problem, i don't have a clue... Is this Charles Law? I know how to change C to K you add 273, but I don't know what figures go where in this formula PV=nRT......
April 18, 2010 by Tracey

What are the relative rates of reaction of primary, secondary and tertiary alkyly halides in an SN1 substitution? Explain the reason for your answer? Thank you so much?
October 14, 2014 by Kim

I really need help on these chemistry problems. Can you please help me work them. Please?
April 5, 2010 by Help please

for a thermodynamics lab, I have to graph the ln K vs. 1/T, so does the ln K go on the y-axis and the 1/T go on the x-axis?
December 8, 2013 by K

Shaking a towel up and down would create what type of wave in the towel? surface
April 5, 2008 by Jon

For Bobpursley Chemistry
I already asked Drbob222 for a substance that i cantake to school wich contains an aromatic compund, I'm not suppose to buy because it must be at home. please help me:0
January 31, 2007 by Iveth

True/False The medium determines the speed through which most mechanical waves will travel. True
April 5, 2008 by Jon

Dear DrBob222 !!! Would you please help me answers the question that I posted. I really don't understand and need help! Please, Thanks
February 19, 2010 by Ashley

Attn: DrBob222
A .326L container holds 0.146g of Ne and an unknown amount of Ar at 30C and the total pressure is 627 mmHg. Calculate the moles of Ar present? (I have calculated temp 308K, pressure is 0.825 atm and moles of Ne are .007) Chem - DrBob222, Wednesday, March 3, 2010 at 3:25pm T is...
March 4, 2010 by Staci

A certain compound contains carbon, hydrogen , and oxygen. When 1.00 grams of this compound are burned in oxygen gas 1.47 grams of CO2 and 0.600 grams of water are formed. When 2.75 grams of the compound are dissolved in 10.0 grams of water the resulting solution freezes at...
January 17, 2011 by Patrick

A wave created when two different waves meet will have an amplitude greater than the individual waves because of. constructive interference
April 5, 2008 by Jon

To: DrBob222
Can you please check my previous science post. As of right now, you are the only science teacher on this site--which is why I am pleading you to. Thank you very much:-)
April 8, 2010 by Sara

chemistry please help drbob222
How much water is needed to dilute 25.0 ml of 0.357 mol/L hydrochloric acid to 0.246 mol/L I got 17.2 is that correct
December 16, 2014 by Anonymous

TO DrBob222 or any science helper
identify the following formulas as acids, bases or salts: HCH3COO NaCL H2CO3 C6H8)7 Mg(OH) NaOH KBr Sr(OH)2 HNO3 please help really urgent :) thanks :)
March 12, 2014 by Anonymous

Science - BTUs Please help
Although I vaguely see DrBob222's concept, I still need some help in the set up. Thank you. A 10 lb. frozen boneless roast needs to be thawed and baked to a temperature of 200 degrees F. The storage freezer maintains a temperature of -10 degrees F. Pork changes from solid to a...
September 3, 2012 by Sejul

I posted this question already but you never replied back :( Consider the following reaction at 298 K: C(graphite) +2Cl2 (g) -----> CCl4(l) Calculate the following quantities. Delta H: -139 kJ/mol deltaS(sys)=? J/mol*K deltaS(surr)=? J/mol*K deltaS(univ)=? J/mol*K My answer...
March 17, 2012 by Leila

DrBob222 help me!!
Please I posted a chemistry question but I havent gotten any answer back please help me, sorry for having so little patience answered below.
May 23, 2007 by Fabiola

not a question: DRBOB222 YOUR AWESOME!!
February 22, 2007 by Jenna

chem: Drbob222
Hi I have a follow up to a question that was answered previously. New question: So when the HPO4(2-) reacts with the NaOH, will the equation be this?: HPO4^(2-) + NaOH --> H2O + NaPO4(2-) But how do I write the equation for the H2PO4^- and HCl? H2PO4^- + HCl --> Here is ...
January 30, 2012 by jean

Chemistry(Please check)
1) The Ka for acetic acid is 1.8e-5. What is the pH of a 3.18M solution of this acid? I did 1.8e-5 = x^2/3.18 x=sqrt 1.8e-5 X 3.18 = 7.56e-3 pH=-log(7.56e-3) = 2.12 The pH is 2.12 2) At 25 degrees celsius, the pH of a 1.75M NaCN solution (the Ka for HCN is 4.0e-10) is ? 4.0e-...
April 2, 2012 by Hannah

DrBob222 my previous question
You asked me to show my work for one of my questions a few minutes ago and i need you to verify my work because you said my answer was wrong
January 12, 2015 by Sandy

The unique rate for the combustion of ethane is 0.44 M/s (a) what is the rate that oxygen reacts? (b) what is the rate of formation of water molecules?
May 2, 2015 by tevon

chem please help drbob222
why can't gravimetric analysis be used to determine the concentration of sodium nitrate (NaNO) in a solution? I think the answer is because NaNO dissolves in water. Am I correct
December 2, 2014 by Morgan

Is HBr an acid? I got mixed up between telling if its a salt or acid, but salts do not have H+ ions, so would it be an acid?
October 12, 2010 by Anonymous

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