# Chemistry - DrBob222 please check and help

122,178 results

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...

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-...

### 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-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 ...

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-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

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...

### 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 - ...

### To Drbob222

. Ksp for Fe(IO3)3 is 10-14. Two solutions, one being iron(III) nitrate and the other being sodium iodate, were mixed. At the instant of mixing, [Fe3+] = 10-4M and [IO3-] = 10-5M. What happens? My answer is that a precipitate forms because Qsp > Ksp. Would you agree? ...

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 ...

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(...

(This homework question has been removed due to a copyright claim submitted by K12 Inc.)

### 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?

### 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:-)

### 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/...

### 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 ...

### Chemistry

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

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

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

### 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 ...

### 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 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

chemistry posted by Naomi today at 8:03pm. The material Magnesium Sulfate What mass of dry material would be needed to make an aqueous solution with a molality of 4 moles/kg solution ? What mass of water is needed? 4 (24.305+ 32.065+ (4 x 15.999)) =481.5 ?Not sure where to go ...

### chemistry

Under the appropriate conditions, NO forms NO2 and N2O: 3NO(g) <--> N2O(g) + NO2(g) Use the values for delta G naught for the following reactions to calculate the value of Kp for the above reaction at 500.0 C 2NO(g) + O2(g) <--> 2NO(g) delta g=-69.7 kJ 2N2O(g) <...

### 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

### 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 ...

### Chemistry-DrBob222

What is the final temperature and physical state if water when 47.50 kJ of energy is added to 15.0 g of ice at -10.0 C? Helpful information: Cs (ice) = 2.1 J/g C Heat of fusion (water) = 6.02 kJ/mol Cs (water) = 4.184 J/g C Heat of vaporization (water) = 40.7 kJ/mol Cs (steam...

### DrBob222 : Chemistry HElp...Please Check

Sorry its not letting me post the entire thing in the other thread .000146612 mols KIO3 x (3 mols I2/1 mol KIO3) x (2 mols S2O3^-2/1 mol I2) mols = .000887972 mols S203^2- Then M S2O3^-2 = .000887972 mols/0.02715 L.M = 0.032400 Therefore the Molar mass of Na2S2O3 is 0.032400

### chemistry help!!! please!!! DrBob222 I need you!!

How many atoms of carbon are needed to produce 0.45 mol Al? 3C + 2Al2O3 4Al + 3CO2 A. 2.6 × 1026 atoms B. 9.7 × 1024 atoms C. 3.0 × 1022 atoms D. 2.0 × 1023 atoms I'm really very stuck with this question. please help me!!!

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, ...

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

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

(DrBob222 please help me) What would be the final temperature of the system if 16.6 g of lead at 138 ◦C is dropped into 23.4 g of water at 8.68 ◦C in an insulated container? The specific heat of lead is 0.128 J/g◦C. Please explain with the numbers plugged in ...

### 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 ...

### drbob222

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.

### 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 ...

What is the [H3O+] for a neutral solution at 50 degrees celsius? I know that kw=[H3O+][OH-] but I am not sure what to do to get the H3O. The value I have for kw=5.76e-14 and I have the pH 6.62 but I do not know what the OH would be. Chemistry(Please help, thank you) - DrBob222...

### 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 -> ...

Please refer to the previous post Chemistry Help Please. Moles of S203^2- = (molarity)(volume): =(0.032400 mol/L)(0.053 litres S203^2-) = 0.03240 moles S203^2- Posted by DrBob222 on Wednesday, October 22, 2008 at 9:37pm in response to GK..please check...Chemistry Help Please I...

### 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...

### Math-which is correct

1 euro is worth 1.2 U.S dollars if I budget 150\$ per night for a hotel room. What is the maximum number of euros I should spend for a room? My answer is 108 euros as a maximum (with an actual number of 107.425) Correct??? * Math-check my answer - DrBob222, Tuesday, September ...

### To Drbob222

I don't get how to get N, please show me cause I don't understand

### chemistry

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

### Honors Chemistry

I got 206.67 g Fe, DrBob222

### chemistry

Using this data, 2 NO(g) + Cl2(g) == 2 NOCl(g) Kc = 3.20 X 10-3 NO2(g) == NO(g) + ½ O2(g) Kc = 3.93 calculate a value for Kc for the reaction, NOCl (g) + ½ O2 (g) == NO2 (g) + ½ Cl2 (g) A. 20.2 B. 2.06 X 10-4 C. 4.49 D. 4.84 X 10-3 E. 0.223 eliminated down to b or d but ...

### chemistry

Using this data, 2 NO(g) + Cl2(g) == 2 NOCl(g) Kc = 3.20 X 10-3 NO2(g) == NO(g) + ½ O2(g) Kc = 3.93 calculate a value for Kc for the reaction, NOCl (g) + ½ O2 (g) == NO2 (g) + ½ Cl2 (g) A. 20.2 B. 2.06 X 10-4 C. 4.49 D. 4.84 X 10-3 E. 0.223 eliminated down to b or d but ...

### 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 ...

### language art CHECK

Will somebody please check this for me and see if i used the words correctly please? Having spent many years as political opponents, the two senators have developed a(n)MUTUAL respect for each other. Please check if it is correct. thank you

### chemistry

DrBob222 - it says my answer should be a number.

1) Nitrosyl chloride (NOCl) decomposes at high temperature. The equation is 2 NOCl (g) -> 2 NO (g) + Cl2 (g) at 227oC Using delta Ho = 81.2 kJ and delta So = 128 J/K, calculate the value of the equilibrium constant for this reaction. I do not know how to start this problem ...

### 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.

### 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

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.

You dissolve 6.55 g of potassium nitrate in enough water to make a 250. mL solution. What is the molarity of this solution ?Answer: 0.0262 Please Check my answer

### 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?

### 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

If you add 0.35grams NaF to 150mL of a 0.30M HF, what is the pH of the resulting solution? To start off would I use the value of 1.4e-11 for F^-^ and 7.2e-4 for HF? Chemistry(Please help) - DrBob222, Tuesday, April 10, 2012 at 12:04am This is a buffer problem. pH = pKa + log(...

### Drbob222

I so need help please tell me some obscure facts about spain

### To DrBob222

can you please have a moment to look at my other previous posts, thanks a lot:-)

### 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 ...

### 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?

Sorry to bug again but can someone check my answers please thank you. 1. Simplify the expression 3w-10w A. 13w B. -7w C. -7 D. 7w 2. Y+2y+3z A. 2y+3z B. 3y+3z C. 2y^2+3z D. 6yz 3. 6r+r-5r A. 2r B. 1r+r C. 0r D. 7r-5r 4. 5x+2(x+6) A. 7x+6 B. 7x^2+12 C. 7x+12 D. 7x (x+6) 5. -3m+...

I posted this up yesterday: I have to use the equation : density= mass/ volume: But i don't know how to find out the volume using the edge length of the unit cell which is 5.88* 10^2 pm. CHemistry....Please help - DrBob222, Sunday, January 25, 2009 at 10:41pm If the edge ...

### chemistry

This refers to your archive question in 2014 Oct 30 at 4.58 posted by Ruzzle and replied by DrBob222. Small query on the solution , which states 1/6 of D atoms will go to form D2O18. Isn't it 2/6 since out of all 6 D atoms 2 is required to form D2O18. Please clarify. Regards ...

### 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 - DrBob222

When sodium burns in air it produces a bright white light and heat energy 2Na + O2 2Na2O ?H = -414kJ/mol What would you expect to be the heat energy associated with the reverse process 2Na2O 2Na + O2 Can you please show the entire calculation with units please? This is what I ...

### DrBob222-Questions

Can you please check these for me. Thank you very much in return:-) For Al2(SO4)3 you gave me Aluminum ion and Sulfate ion. These are the rest: CaCl2 = Calcium ion and Chlorite ion Na2O = Sodium ion and Oxygen ion AgCl = silver ion and chlorine ion Na3PO4 = Sodium ion and ...

### chemistry (DrBob222)

Calculate the value of Ecell for the reaction of cobalt(II) chloride and zinc metal, given the specific concentrations listed. Zn(s) | Zn2+(0.21 M) || Co2+ (0.21 M) | Co(s) Okay, so I keep getting -1.04 and -1.06 when I do this problem. I have used log k=-nEcell/0.0592 and ...

### chemistry (DrBob222)

Calculate the value of Ecell for the reaction of cobalt(II) chloride and zinc metal, given the specific concentrations listed. Zn(s) | Zn2+(0.21 M) || Co2+ (0.21 M) | Co(s) Okay, so I keep getting -1.04 and -1.06 when I do this problem. I have used log k=-nEcell/0.0592 and ...

### CHEMISTRY

really really need help w/this problem I think i figured it out but i have to be sure i did it right in order to do others similar to it please help thanks Metal Specific Heat (J/g-C) Al (s) 0.900 Au(s) 0.129 Cu(s) 0.385 Fe(s) 0.444 Hg(l) 0.139 H2O(l) 4.184 C2H5OH(l) 2.46 A ...

Name these: a) CH2=CH-CH=CH2 b) CH3-CH=CH-C(TRIPLE BOND)CH c) CH3-CH2-CH2-CH(Cl)-CH(Br)-CH3

### Chemistry

In which direction will the net reaction proceed X(g)+Y(g)<---->Z(g) Kp=1.00 at 300k for each of these sets of initial conditions? a) [X]=[Y]=[Z]=1.0 m net reaction goes to the left net reaction goes to the right reaction is at equilibrium I chose 3 for a. b) Px=Pz=1.0 ...

### Math 157

Can someone please help me. At a quality control checkpoint on a manafacturing assembly line, 10% of the items failed check A, 12% failed check B, and 3% failed both checks A and B. a. If a product failed check A, what is the probability that it also failed check B? b. If a ...

### Math

Can someone please help me. At a quality control checkpoint on a manafacturing assembly line, 10% of the items failed check A, 12% failed check B, and 3% failed both checks A and B. a. If a product failed check A, what is the probability that it also failed check B? b. If a ...

For the system CaO(s) + CO2(g) = CaCO3(s), I added 1.00 mol of CaO(s) to 1.00L of 0.500M CO2(g) at 200 oC. At equilibrium the [CO2] = 0.150M. What is the value of Kp for this reaction? Kp would = CaCO3/(CaO)(CO2) I do not know what to do with the 0.500M and 1.00mol. Chemistry(...

Ok I was wondering if you could check these 3 problems please. I am suppose to set these equations equal but I am not sure if did them right. I think I accidently solved these systems as substitutions. The answers are suppose to be in coordinate pairs. 1) x - y = 11 -3x + y...

### Chemistry help (DrBob222)

propane (c3h8) is burned in oxygen to produce carbon dioxide and water. The heat of combustion of propane is -2012 kJ/mole. How much heat is given off when 3.0 mol C3H8 are react with 10.0 mol O2? Thanks, and please if possible show all steps!

### 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...