# Chemistry-DrBob222

58,820 results

### Chemistry-DrBob222

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 ...

### 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.

### chemistry

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/...

### Chemistry-DrBob222

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 ...

### chemistry

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 ...

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 ...

### 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...

### DrBob222

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

Thanks a lot I get it now!!!!!! From Adam To DrBob222

### To DrBob222

DrBob222 do you know anything about Heredity and Punnet Squares?

### Chemistry and @DrBob222

Sorry for the mix up -- here's what DrBob222 posted for the Chm or Chemistry question: What subject is CHR? If you don't label the subjects correctly the proper tutor won't know you need help. This question can't be answered as posted. You need the concentration of the H2SO4 ...

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...

### Chemistry

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...

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 ...

### chemistry

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 ...

### Chemistry

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 ...

### Chemistry

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...

### 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...

### chemistry

Drbob222 that does not help. got anything else up ur sleeve?

### Honors Chemistry

I got 206.67 g Fe, DrBob222

### chemistry

DrBob222 - it says my answer should be a number.

### 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?

### Chemistry-DrBob222

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 ...

### Thanx DrBob222

Thank you sir for helping me out with those chemistry problems.

### DrBob222

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 ...

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-...

### Chemistry

Is DrBob222 available tonight? Please let me know, I need some chem help.

### chemistry

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

### Chemistry (DrBob222)

Is the relationship between delta G and Temperature inverse or direct?

What is the pH of a 5.06E-2 M aqueous solution of sodium acetate? I know that I would set this up the same way I did for the previous question that I posted. I am just confused on how to find the Ka. I know it is kw/kb but for what compound is what I do not know. Chemistry(...

### Chemistry

Just WHO IS DRBOB222? AND WHY ARE YOU SO AMAZING? PLEASE TELL US MORE ABOUT YOURSELF!

### chemistry

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

### chemistry..

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

### chemistry

DrBob222 No. 0.30 isn't the correct answer either. I'm going to ask my prof about it tomorrow.

### chemistry

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?

### college chemistry

DrBob222. when you move ice from zero to final T. Do you add 100 cal.?

### chemistry

Hey DrBoB222 I was wondering if you could help me with that problem just a little bit ago again?

### Chemistry

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 - ...

### chemistry

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?

### chemIstry

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

### Question,drbob222,math

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 ...

### 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-

### math,drbob222

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...

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, ...

### 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 :)

### 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 -> ...

### Chemistry

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......

### Chemistry(DrBob222)

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?

### Chemistry-DrBob222

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...

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 ...

### chemistry

A reaction has a rate law, rate = kA]B]^2 What is the overall order of the reaction? a. 2 b. 3 c. 0 d. 1 e. 4 chemistry - DrBob222, Friday, February 17, 2012 at 10:53pm The overall is the sum of the orders of each component. still don't get it but guessing A

### Chemistry *DrBob222

Posted by Jamie on Sunday, June 20, 2010 at 3:36pm. You are given three test tubes that contain colourless liquid. One test tube contains benzene, another contains ethanol, and the third contains 2,4-hexadiene. Design a procedure that will tell you the contents of each test ...

### chemistry

For the reaction, A = B + C, the rate law is kA]. If it takes 80.0 seconds for 70.0% of a 10.0 gram sample of A to be transformed into products, what is the value of the rate constant? a. 0.00450 s-1 b. 0.0290 s 1 c. 0.00530 s-1 d. 0.0150 s-1 e. 5.40 s-1 chemistry - DrBob222, ...

### College Chemistry

Calculate the electrode potential of a copper half-call containing 0.05M Cu(NO3). E^0 Cu2+/Cu = 0.337 V College Chemistry - DrBob222, Tuesday, April 20, 2010 at 5:19pm E = Eo - (0.0592/n)log[(Cu)/(Cu^+2)] Substitute 2 for n and 0.05 M for Cu^+2 and 0.337 for Eo. Solve. Am I ...

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

### chemistry to @DrBob222

What is the reason for considering N2 has a boiling point lower than O2,because of its low molecular mass. Just curious about that old reason...

### Chemistry

Which aqueous solution below is expected to have the lowest freezing point? Assume 100% dissociation for ionic species. 1)0.25m MgBr2 2)0.30m Na2SO4 3) 0.50m KCl 4) 1.0m sucrose 5) 0.40m Cr(NO3)3 I think that the answer is 0.30NaSO4 but I am not positive. Is this correct? ...

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...

### Chemistry to DrBob222

Regarding my question on display.cgi?id=1496901710(I can't post URLs) Can we apply the formula PM=dRT seperately to the systems before and after being heated,and solve this one?

### Chemistry

Assuming that the smallest measurable wavelength in an experiment is 0.330 fm(femtometers), what is the maximum mass of an object traveling at 157 m·s^–1 for which the de Broglie wavelength is observable? mass = ? kg Chemistry - DrBob222, Monday, October 29, 2012 at 12:29am...

### Chemistry

Assuming that the smallest measurable wavelength in an experiment is 0.330 fm(femtometers), what is the maximum mass of an object traveling at 157 m·s^–1 for which the de Broglie wavelength is observable? mass = ? kg Chemistry - DrBob222, Monday, October 29, 2012 at 12:29am...

### chemistry

What is the concentration of the Mg2 ion in solution when [CO3-2] = 0.25M given that the Ksp= 6.82 x 10-6 for the following reaction MgCO3-------->Mg +. CO32- Chemistry - DrBob222, Friday, November 11, 2011 at 5:34pm Ksp = (Mg^2+)(CO3^2-) Substitute 0.25M for CO3^2- and ...

### Chemistry-DrBob222

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?

Thanks DrBob222 for previous answers. Question: Balance the following reactions by the oxidation number method. a) I2 + HNO3 --> HIO3 + NO2 + H2O b) MnO4- + H+ + Cl- --> Mn2+ + Cl2 + H2O

### Chemistry

When titrating 50.0 mL of 0.10 M H2SO4 with 0.10 M NaOH, how many mL of NaOH will you have added to reach the 1st equivalence point? I am confused... What H2A problem? Chemistry-Dr.Bob222 - DrBob222, Tuesday, April 12, 2016 at 1:49am Refer to the H2A problem above BUT you only...

### chemistry

Gasohol contains ethanol (C2H4OH)(l), which when burned reacts with oxygen to produce CO2(g) and H2O(g). How much heat is released when 12.5g of ethanol burns? C2H5OH(l) + 3 O2(g) --> 2 CO2(g) + 3H2O(l) Delta H = -1368kJ Chemistry - DrBob222, Wednesday, May 19, 2010 at 9:...

### Chemistry

See bottom Patrick 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 ...

### College Chemistry (DrBob222)

Use the Nernst equation to calculate the iron (II) concentration for the following iron/copper electrochemical cell when [Cu2+] = 0.012 M and Ecell = 0.750 V at 35°C. Cu2+ (aq) + Fe (s) --> Cu (s) + Fe2+ (aq)

### Chemistry

Calculate the molar solubility of MgCO3 in a solution that already contains 1.7×10−3 M sodium carbonate. MgCO3 Ksp = 6.82 x 10-6 IMPORTANT NOTE: You must use the quadratic equation to solve this problem. (DrBob222- thank you so much for all your help!)

### Chemistry

@DrBob222 I got the last question that I posted wrong and I solved it the same way. Could you show me the answer and how you got it? My test is Friday and this is a practice problem. Suppose that 30 mL of 0.5 M CsOH and 55 mL of 0.1 M NaHS are mixed. What is the K for the ...

### Science (Chemistry)

Hello DrBob222 Regarding the answer you gave me thank you very much. However when you expand the denominator, I don't get -0.14 but I get -0.28. I get that because when I first expand I get 0.0049 - 0.14x - 0.14x + 4x^2. So when I simplify that I get -0.28x. So could you ...

### chem

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 ...

### Chemistry-DrBob222

What would the pH value for grapefruit juice be? >7, 7, <7 It wouldn't be 7 because its not neutral, it wouldn't be greater than 7 because that's considered to be basic, I think it would be less than seven because it has acid in it. So it would be <7?

### Chemistry- DrBob222

0.2g of an organic sample W, analysed by combustion analysis results in 0.48g of CO2 and 0.1636g of H2O. We had a second sample 0.2g of W again producing 0.0618g of ammonia. Show that only C, H and N exist in W and find its emperical formula.

### Chemistry help drbob222

Which of the following processes would result in a negative entropy change? A. Leaves falling off a tree B. A deck of cards falling on the floor C. A piece of cake crumbling as it is cut D. A student filing papers I think d

### Chemistry

Here is my question and I,m hoping I worked the problem out correctly. A 10-g mass of krypton occupies 15.0 L at a pressure of 210 kPa. Find the volume of the krypton when the pressure is increased to 790 kPa. V2 = V1 x P1/P2 V2 = 15.0 L x 210 kPa/790 kPa = 3.98 L or rounded 3...

### Chemistry -- DrBob222

A gas initially at STP is heated to 50°C keeping the volume constant. What is its new pressure? I used this formula: P1 = 1 atm T1 = 273 K T2 = 323 K solve for P2 P2 = P1 (T2/T1) But, where do I use the 50 degrees C? Also, is my answer correct: P2 = 1atm x 323K/273K = 1.18 atm

### Chemistry - DrBob222

C6H14 + Cl2 in UV light Below are 5 products, say which one cannot be a product, prove this by showing how each of the other products were formed from the equation above. 1-chlorohexane 2-chlorohexane 2,2-dichlorohexane dodecane hex-1-ene

### College Chemistry (DrBob222)

The decomposition of HCO2H follows first-order kinetics. HCO2H(g) CO2(g) + H2(g) The half-life for the reaction at a certain temperature is 44 seconds. How many seconds are needed for the formic acid concentration to decrease by 73%?

Thank You!

### Chemistry

i need help. Calculate the pH of a 0.24 M CoCl3 solution. The Ka value for Co(H2O)63+ is 1.0 10-5. how do u do these with like the Cl there? Responses Chemistry - DrBob222, Monday, February 16, 2009 at 12:35am Just ignore the Cl^-. Co(H2O)6Cl3 ==> Co(H2O)6^+3 + 3Cl^- Then ...

### Chemistry

Fluorine reacts with oxygen to yield oxygen difluoride. 2 F2(g) + O2(g)<--> 2 OF2(g) What is the value of K if the following concentrations are found at equilibrium: [O2]= 0.200 mol/L, [F2]=0.0100 mol/L, and [OF2]=0.0633 mol/L Chemistry - DrBob222, Thursday, March 1, ...

### Chemistry- DrBob222

Can you please write the isomer name though? I will draw it from that. Write an isomer of structure for a), b) and c) and name them. a) 3,3-dimethylpentane b)3-methyl-4-ethyl-1-hexyne c)3,3,4-trimethyl-1-pentene

### chemistry urgent

hydrogen gas is collected in a bottle, and the pressure of the gas is 892 torr at 24 °C. what is the pressure of hydrogen gas when the temperature decreases to 20 °C? chemistry - DrBob222, Tuesday, November 30, 2010 at 1:25pm (P1/T1) = (P2/T2) Dear Dr Bob: is this a right ...

### To DrBob222

What is 14/4 as an integer?

### chemistry

Posted by Jenni on Monday, December 13, 2010 at 3:32pm. Determine the molarity of nitrate ions in a solution prepared by mixing 25.0 mL of 0.50 M Fe(NO3)3 and 35.0 mL of 1.00 M Mg(NO3)2 Please explain fully do not know where to start? chemistry - DrBob222, Monday, December 13...

### chemistry

Effusion/Diffusion Chemistry Help!!! If 4.83mL of an unknown gas effuses through a hole in a plate in the same time it takes 9.23mL of Argon, Ar, to effuse through the same hole under the same conditions, what is the molecular mass of the unknown gas? (146amu) Responses: * ...

### DrBob222

Im in the 10th grade in Chemistry 1 Honors. Im learning to write a chemical equation. Im confuse on that statement i was given for my homework. The products and reactants are just magnesium Sulfide and magnesium and sulfur? Then why are they talking about yellow crystalline ...

### chemistry

What mass in grams of potassium hydroxide is cntained in 500 mL of solution that has a pH of 11.5? For Further Reading chemistry - DrBob222, Sunday, April 6, 2008 at 12:09am pH = 11.5 pOH = 14 - 11.5 = 2.5 pOH = -log(OH^-) ] 2.5 (OH^-) = ?? KOH ==> K^+ + OH^- This is a ...

### to drbob222

thank you so very much