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Chemistry- Drbob-help

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For DrBob
Hey DrBob, I posted an answer to you question on my lab report just to let you know what the y= and r^2 is

Drbob, your explanation is very clear and I learned alot out of it. I also have one last question to ask you. I posted it at my last post.

DrBob, if you're still on...what do I do for NaCl??

Can you reply to my last post on chemistry? thanks alot.

Hi DrBob, I was wondering if you can help me with a few questions? If you can I would truly appreciate your time

Chemistry - DrBob Help!
Draw product for chlorination of 2methylbutane through a 2nd radical

Last chemistry post
Can someone please reply to my previous post about chemistry preferable DrBob since he was helping me on it, but anyone is fine.

in response to DrBob, the textbook gives this equation for the problem. So if you could balance it as it is written, great!

question from my previous post answered by DrBob - is this because this acts as a polyprotic acid, or because the ratio in the Henderson Hasselbach for HA/A- remains the same?

Just wanted to say thank you to DrBob for responding back even if he wasn't able to answer the question posted on Thur. 4/14/2011. If there is anyone else who can answer I'd appreciate it.

chemistry DRBOB
Calculate the hydrogen ion concentration, in moles per liter, for solutions with each of the following pH values. pH=1.10 im guessing that this is what i did in my previous question except now i have to do it backwards. but i don't know how to do the calculations on the ...

Chemistry DrBob please answer
A reaction at 3.24 atm consumes 5.10 L of a gas adiabatically (q = 0). Calculate the change in internal energy of the system (in kJ). I know that I have to use w=-p deltaV but how do i find the Final and Initial volumes?

Chemistry (Analytical) followup
Thanks DrBob for answering the question! I was assuming it was something similar to that, but my confusion is that a follow up question is asking what happens to the dissolved Ca2+ if the pH is reduced to 2, so the pH has some effect, but I don't know what.

Can you please help me to work out the addreviated structural formulae of hydrolysis of tocainide? Won't it be the -NH2 group that hydrolyzes? ArNH2 + HOH ==> ArNH3^+ + OH^- Check my thinking. Thanks That is exactly what I thought it would be. Thanks again DrBob.

Chemistry- DRBOB!! PLEASE?
molecular orbital theory? my teacher was like "im not teaching it, but its going to be on your test" can you please summarize what it is, i read the online sites,tehy don't make sense...

Can you reply to my last post? thank you.

help below please

help with below questions please and thank you

Hi DrBob, you are an inspiration to my brother since he tells me you help so many people including himself with your generosity.Thank you!. My brother was wondering if you will be online later tonight since he needs help with three questions when he gets back from nihgt school?

When burning a Magnesium Ribbon, would the color (the white dust) that it changed to be a chemical change? Or how about the spark it makes (I am just in basic chemistry, so that spark might be counted as a chemical change)? So far I got from the help for Drbob: 1.Reacts with ...

theres a response for u on my previous question

chemistry HELP DRBOB
Calculate the sodium ion concentration when 80.0 mL of 4.5 M sodium carbonate is added to 30.0 mL of 1.0 M sodium bicarbonate. how do i solve this I don't really know where to begin.. is there a formula for finding concentration because we don't learn this in class we ...

12th grade chemistry
Thanks for your answer DrBob. I am still stumped.The question I was asked to answer is Do acetic acid and stearic acid undergo controlled oxidation reactions? Explain why/why not and draw an equation to illustrate the answer.

no question - just thank you "drbob", you've answered a few of my questions.

Can you please show me how to set up these conversions (how to do each of these conversions) Question- The pressure of gas is measured ay 550 mm Hg. Calculate the pressure in: a. Torr b. lb/in2 c. atm d. in Hg Can someone other than DrBOB answer this please!

Can you please show me how to set up these conversions (how to do each of these conversions) Question- The pressure of gas is measured ay 550 mm Hg. Calculate the pressure in: a. Torr b. lb/in2 c. atm d. in Hg Can someone other than DrBOB answer this please!

Hi DrBob, thanks for getting back to me on the earlier related question, but to be honest I am COMPLETELY lost on this! Can you please show me how your worked out the answere using the figures from the question. Thanks. Question: (a) How much sodium bicarbonate (mass) would ...

please answer below i have a question on something already asked thanks

WHAT IS PK2? pK2 for H3PO4. Look in your text for k2 for H3PO4. My text, but it's an OLD OLD one lists k2 of 6.2E-8 and pK2 = 7.21. DRBOB. It is the same in my reference as well, 6.23E-8 or pK2=7.21 at 25C.

I asked this question earlier that drbob explained but i still do not really understand what to do. can you please make it clearer? the average pH of healthy human blood is 7.4. how many moles of H+ ions are free in your blood. The average person has approx. 5 L of blood. ...

Chemistry - DrBob PLEASE
A glass of ice water was made by adding six 25 g ice cubes to one liter of water. If the water was initially 25C and the ice cubes were initially at -15C, what is the final temperature of the ice water? (I don't know how to get it.)

Please help me N2O5(g) + H2O(l) --> 2HNO3(l) delta H° = -76.2 kJ H2O(l) --> H2(g) + 1/2O2(g) delta H° = 286.0 kJ 1/2N2(g) + 3/2O2(g) + 1/2H2(g) --> HNO3(l) delta H° = -174.0 kJ Calculate delta H° for the reaction 2N2O5(g) --> 2N2(g) + 5O2(g)

Please help me N2O5(g) + H2O(l) --> 2HNO3(l) delta H° = -76.2 kJ H2O(l) --> H2(g) + 1/2O2(g) delta H° = 286.0 kJ 1/2N2(g) + 3/2O2(g) + 1/2H2(g) --> HNO3(l) delta H° = -174.0 kJ Calculate delta H° for the reaction 2N2O5(g) --> 2N2(g) + 5O2(g)

Chemistry DrBob
This is what i posted up a while back... i got to a using 0.520= a (.202M) and got a= 2.57 but now i don't know where to go from there with the ICE The standard solution of FeSCN2+ (prepared by combining 9.00 mL of 0.200 M Fe(NO3)3 w/1.00 mL of 0.0020 M KSCN) has an absorbance...

when you said that a is the constant ,and b is the path length what do you mean?? would the constant be 10 because for wavelength we increased it by 10 each time??

DrBob I answered the ??
I rote the qestion Amy... please check your question below. I answered Back again!!

Drbob Chem
Why does it not matter whether the OH groups are cis to one another in the furanose ring or trans to one another? Please help!

Thank you for the informative answer yesterday. I hope you can help me with this one too. Thanks S(subscript 8) + O( subscript 2) -> SO3 Could you explain why it O3 when S valence is -2? Thanks

Chemistry DrBob
You told me the steps on a previous post but i must have forgot how to work out absorbance or ICE cus i keep getting the wrong answer ... The standard solution of FeSCN2+ (prepared by combining 9.00 mL of 0.200 M Fe(NO3)3 w/1.00 mL of 0.0020 M KSCN) has an absorbance of 0.520...

Hi DrBob thank tou for your help so far its really inspiring I must say:) I have another question though:P Use the table to predict wheter a precipiatate forms if: 25.0 mL of 0.010 mol/L silver nitrate is mixed with 25.0 mL of 0.0050 mol/L potassium chloride My teacher says ...

to everyone
I'd just like to say thank you all to the volunteers and fellow questioniers for helping out a lot. Your help is very appreciated. You are welcome. DrBob did a major work with you, and you should be appreciative. your welcome!

The question I am having trouble with is: Scientists originally were uncertain whether the oxygen gas produced during photosynthesis came from CO2, H2O, or from both. How could radioisotope tracers be used to settle that question? Chemistry - DrBob222 6CO2 + 6H2O ==> ...

The voltage generated by the zinc concentration cell described by, Zn(s)|Zn2+ (aq, 0.100 M)||Zn2+ (aq, ____ M)|Zn(s) is 24.0 mV at 25 °C. Calculate the concentration of the Zn2 (aq) ion at the cathode. Hi, I posted this question awhile back but I think it got drowned out so I...

Chemistry; to drwls or drbob
i think i have posted this before except i forgot to put the decimal in the temperature. i was hoping you could help me now that it might make more sense. The total pressure in a flask containing air and ethanol at 25.7 C is 878 mm Hg. The pressure of the air in the flask at ...

Determine the unknown quantity in the following cell at 298.15 K. Pt(s) | H2(g, 1.0 bar)| H+(pH = ?) || Cl -(aq, 1.0 mol·L-1) |AgCl(s), Ag(s), ΔE = +0.36 V. (DrBob) I still wasn't able to figure out the other one--I posted again after that one, but I know there are a lot...

To 400mL of a 0.1 M CH3COOH solution(Ka=1.8 x 10-5),two subsequent additions of 100mL of 0.2 M NaOH solution have been done.determine the solution pH after each addition. Drbob,I don't understand this problem how to solve.Can you help me and give me the full calculation.

Solve the equation using the Quadratic Formula 5xsquared+13x-6=0 i think it is -2/5,3 5x^2 + 13x -6 (5x -2)(x +3)=0 You are correct. From Bob Pursley's work you can see that his solution gives +2/5 and not -2/5. The +2/5 is correct. drbob is right on that. the solutions are 2/...

DrBob has given you the equation to use: k2 = [H^+][SO4^-]/[HSO4^-] and the values to substitute [H^+] = 0.01 + x [SO4^-2] = x [HSO4^-] = 0.01 - x k2 = 1.2 x 10^-2 you need to substitute these and solve for x. Remember that you are after 0.01+x [H^+] to calculate the pH. is ...

Chemistry-Plz see this DrBob
I am sorry I do not know what happens the symbolism, so I just deleted the symbols. Is it works for you that deleted the symbols? Using standard reduction potentials, calculate the standard Ecell, emf, for each of the following reactions. State if each reaction is spontaneous ...

Suppose one card is selected at random from an ordinary deck of 52 playing cards. Let A= event a diamond is selected B=event a club is selected Determine P(A|(not B)) DrBob said it is 1/3 but how did he get it? I keep getting answer 1 or 21/26

Chemistry DrBob
What is the pH of the solution created by combining 2.30 mL of the 0.10 M NaOH(aq) with 8.00 mL of the 0.10 M HCl(aq)? with 8.00 mL of the 0.10 M HC2H3O2(aq)? mL NaOH pH wHCl pH wHC2H3O2 2.30 ________ _________ What are the pH values if you take into account that the 8.00 mL ...

To DrBob222
I really thank you for helping me with my problems, and not directly giving me the answer but assisting me so I can fully get it, I think your the best helper on here and I really appreciate your help!!!!!!!!!!!!!!!!!!!!!!!!!! Dr Bob is truly super. you've helped me a couple ...

Attn: DrBob
A household bleach solution contains 5.25% (by mass) NaClO. How many moles of NaClO are needed to make 1000 L of the solution? (density = 1.07g/mL) This is the complete question on my assignment. It's 1000 L.

Chemstry Help Drbob!
How much heat (in kJ}) is required to vaporize it? (Assume a density of 1.00 g/mL ) I have this 60.0ML/ 1.00 g/ml = 60grams 60/153/81 g/mol = .3900916715 moles .3900916715 moles / 43.9 kj/mol = 17.122 And it keeps telling me the answer is wrong.

Chemistry DrBob
I don't understand how you get the answer. I really don't understand any of this, how do I set it up with the numbers? once i get how to do this, then i feel i will understand how to set these up from here on out. so if you could, show all your work, thanks (A). A reaction ...

How would i explain the readiness of allyl alcohol to react with the Lucas test???? Thanks!! ------------------- I still don't understand-- I know Lucas Test is best for tert carbocations but 2-propen-1-ol gives secondary carbocation at best even with rearrangement? Is that ...

okay you talked about using a graph and we made one so this is the formula from it. y = 2.2019x y = absorbance x= concentration so if i have an absorbance of .02, do i do... .02/2.2019= .0091 .0091 would be x so it would be the concentration is this right???

chem 4 DrBob
It takes 96,485 coulombs to plate 1 equivalent Cr(52/6= about 8.67 g). To plate 200 g will require how many C? 96.485 x (200/8.67) = ? C Then amperes x time = C You know A and C, solve for time (in seconds) where does the 6 come from?

Is 3:1:1 hexane/acetone/acetic acid a more polar or non-polar solvent? more polar or non-polar solvent than what? 3:1:1 hexane/acetone/acetic acid would be considered quite a polar solvent mix. But as DrBob says more polar than with what?

chemistry- DrBob
Last week i did a lab and i just wanted to show you my results because my computer was acting weird when i used the voltage probe.(I just needed you to check that the cathode and anodes and voltages make sense) CuSO4(cathode)and Al2(SO4)3 (anode)--[0.050V] cuSO4(anode) and ...

Damon or DrBob please help..chemistry/physics
Question: 0.37 litre of an ideal monatomic gas (Cv,m = 3R/2) initially at 51 °C and 36 atm pressure undergo an expansion against a constant external pressure of 1.06 atm, and do 2.3 kJ of work. The final pressure of the gas is 1.06 atm. Calculate the change in enthalpy, Δ...

Boiling point (DrBob)
If you add 2g of NaCl to 23mL of water, what is the boiling point? . 2 g/molar mass Salt = 58.4425 mole of salt delta T = Kb*m delta T = 0.512 x 0.23 = 0.113 or about 113 C. I tried to model this problem like you did, but I don't know if I did it correctly.

chem 101
60F is 15.55 C 180 F is 82.22C delta T = 82.22-15.55 = 66.67 q = mass x specific heat x delta T q = 100g x 4.184 x 66.67 q = 278,947 = 279 kJ. Burning alcohol (46 g ethanol) provides 1238.43 kJ/mol. We want to know how many g ethanol to burn to provide 279 kJ. 46 g x (279/1238...

Calculate the initial molarity of KNH2 and the molarities of K+, NH3, OH-, and H3O+ in an aqueous solution that contains 0.75 g of KNH2 in 0.255 L of solution. You may ignore the reaction of NH3 with water. I already found the initial molarity, but I am not sure how to find ...

eth drbob
Can you help me I read your post on Pyne and culturism. I don't think I am qualified to critique your paper the way it should be critiqued. Some general suggestions are as follows: Start sentences with capital letters. Watch the spelling. You have a number of sentences that ...

Formula for calculating cubic feet. length(in feet) x width(in feet) x height(in feet) = volume in cubic feet. Thank you DrBob That's for a cube or four sided regular figures. For a cylinder, it's pi*(radius2)*height and there are other formulas for other figures.

Early Child Ed.
Yes. Temper tantrums are usually caused by a child's frustrations and is strictly emotional. B. is the best answer. By the way, beware of any answer that says "always" or "never." When you're working with people, there are almost no situations that are that black and white as ...

Which of the following reactions is exothermic? 1. Na(s) --> Na(g) 2. Na(g) --> Na+ + e- 3. Cl2(g) --> 2Cl(g) 4. Cl(g) + e- --> Cl-1 My guess is 4, but I'm not sure Here is what you do. For 1, do we think it will take energy to change Na as a solid to Na as a gas. ...

chemistry- DrBob
summarize part a ( the data i showed you) in a data table containing heading: anode, cathode, overall cell reaction, and cell potential . for each cell combination, write the anode half reaction, the cathode half reaction, the overall reaction in the cell notation ( the ...

What is the pH ( 3 significant digits) of a 0.01 M solution of sulfuric acid? Hint is that the first ionization constant is "large", and the second is finite, and the [H+] donated by the second equilibrium depends upon the amount of [H+] already donated by the first ionization...

Chemistry to DrBob
Dr. bob could you please check this work cus i can't seem to get it right the first step of the synthesis is described by the reaction below. When 1.750 g of Fe(NH4)2(SO4)2 6H2O is mixed with 13 mL of 1.0 M H2C2O4, the theoretical yield of FeC2O42H2O is ???? grams. Fe(NH4)2(...

I have one more question DrBob, I have draw a structure of this polymer CH2=CH-CH-OH ' CH3 and identify the monomer units. Would the mononer unit be this: CH2-CH-CH-O ' CH3 AND WOULD THIS POLYMERIZATION BE A CONDENSATION TYPE? Paula--I am not an organic chemist but this doesn'...

Sorry DrBob, it's me again! Here's the info: Antacid Brand: Life Concentration of HCl: 0.1845 M Concentration of NaOH: 0.1482 M Trial 1: 1.Mass of Table: 1.2173g 2.Volume of HCl added: 75.0 mL 3.Milliomoles of HCl added:(0.1845M x 75.0mL= 13.84 mmoles 4.Volume of NaOH used: 17...

Sorry DrBob, it's me again! Here's the info: Antacid Brand: Life Concentration of HCl: 0.1845 M Concentration of NaOH: 0.1482 M Trial 1: 1.Mass of Table: 1.2173g 2.Volume of HCl added: 75.0 mL 3.Milliomoles of HCl added:(0.1845M x 75.0mL= 13.84 mmoles 4.Volume of NaOH used: 17...

physics- drbob can u plz help me???
VERY IMPORTANT FOR AN ESSAY ASSIGNMENT. PLEASE HELP ASAP! THANK U VERYYYYY MUCH! 1. What force is needed to give a mass of 25 kg an acceleration of 20m/s squared? 2. A force of 6N acts upon a 2-kg mass. What is the acceleration of the masS? 3. It takes a force of 50N to give a...

A mixture containing 19.8 moles of H2 and 7.2 mole of I2 was allowed to reach equilibrium in a 5 L closed vessel at ToC according to the equation: H2 (g) + I2 (g) 2HI (g) At equilibrium, 14 moles of H2 was present. The equilibrium constant for this reaction is denoted as Kc(1...

Hello, need help in answering this question what does race and ethnicity mean to you. The way I interpret the question, it wants YOUR opinion. You may gain some useful insight by going to and using both the dictionary and the thesaurus. The on-line ...

Chemistry- Drbob-help
I have placed the answer I got please help. A student makes a solution by dissolving 55.8 grams of potassium hydroxide in 875.0 grams of water. The resulting solution has a density of 1.07 grams per milliliter. 1. What is the volume of this solution? 870mL 2. Calculate the % ...

How do you make a venn diagram of the 6 branches of chemistry? (Inorganic chemistry, organic chemistry, biochemistry, nuclear chemistry, physical chemistry, and analytical chemistry) like where would they go in the 3 circles

drbob you helped me with this problem the other day but i have a question. -i changed 500mL of ethanol to grams then to mol. i was wondering if i then used 1000mL or 500mL of water to change to kg? The "proof" of an alcoholic beverage is twice the volume percent of ethanol, ...

What is the chemically combined substance of a hydrogen atom and a helium atom. please help me because i really don't know this is confusing really please and thankyou Hydrogen atoms don't normally combine with helium atoms. In fact, helium atoms don't combine with much of ...

does methane have anything to do with ozone depletion? What Drainage basin does Michigan belong to? I have answered this one a couple of times already. Can I direct you to the statement in the conclusion in DrBob's ...

Chemistry- Drbob-help#3
I still need help with #3 I'm not sure how I got 1.14M. I have tried to do the problem over, but I not coming up with my original answer of 1.14M. Somehow I am missing a step. Please show work for the 1.14M Thanks Question#9 reads exactly as written. A student makes a solution...

Hi DrBob, Sorry about that, I wasn't very clear! Can someone please help me complete these calculations for my lab; I am having some trouble. A. Standardization of Na2S2O3 -Mass of KIO3 in 100mL = 0.09600g -Calculate Molarity of KIO3= ? Please check: 0.09600g/(214.0g/mol)=4....

physical science
Which electron cannot occurr? a) 1s^22s^1 b) 1s^2 2s^2 2p^6 3s^2 c) 1s^2 1p^6 2s^2 2p^6 d) all can occurr How do I figure this out? s orbitals can contain 2 electrons maximum and p orbitals can contain 6. I do not see this condition being violated in any of the configurations ...

got another question for DrBob please? The composition of hydrogen selenide can be determined by heating tin (Sn) in a measured volume of gas. The hydrogen selenide is decomposed, producing solid tin selenide (SnSe) and hydrogen gas. If the temperature and pressure are ...

Dr.Bob, yesterday you told me : "The best way I think is to show examples. 12Mg = 1s2 2s2 2p6 3s2 Here the 1s orbital is lower than the 2s and they are lower than the 3s etc." 19K = 1s2 2s2 2p6 3s2 3p6 3d0 4s2 Here the 1s is lower than the 2s and those are lower than the 3s ...

For DrBob
Methods and Materials: The starting materials for this lab were: a crucible, breakfast cereal (Kix), bun cent burner, 100 mL beaker, hot plate, 100 mL volumetric flask and stopper, a funnel and filter paper. First off by taking the breakfast cereal crushed up and placing it ...

2/3(7/8-4x)-5/8=3/8 I do not underdtand the steps?? Do I find a common denominator for all the fractions? Step 1. Clear the parentheses. Step 2. Multiply through by 24. Step 3. Solve for x. when I clear the parenthesis do I distribute 2/3 or do I just take out the parenthesis...

science (chem)
what is the chemical eqzn of Na2CO3 + HClO4? Na2CO3 + HClO4 ==> NaClO4 + H2O + CO2 I will leave it for you to balance. how did you get that DrBob The rule on carbonates is: An acid added to a carbonate yields carbon dioxide, water, and a salt. oooh so you had to know that ...

balanced equation
? MnO4– + ?H+ + ?C2O42– --> ?Mn2+ + ?H2O + ?CO2 what's the balanced equation? correct coefficients? is it 1MnO4- + 2H+ + 1C2O42- --> 1Mn2+ + 1H20 + 2CO2 ? c2042..? are you missing parenthesis somewhere? oh i see, no i believe this is correct: MnO4- + 8h+ + C2042- -&...

Maybe you know this one..
Heyy, I posted this before but it kinda got pushed down and ignored, and I was hoping maybe DrBob might have an idea since no one else did! okay I have this question about chemistry and its driving me nuts. It feels like I am so close but am just missing something. The ...

I am new and I have questions. Are there any teachers in this website? If there are teachers in this website WHAT ARE THEIR NAMES? I could write to them in this website when I need help with my homework LIKE: Name:Kaveri Subject: To:Teacher (Name of the teacher) If there are ...

What volume of a 0.2 N NaoH solution do you expect to use in order to titrate 25ml (sample out of 250ml) of a 0.200 N oxalic acid solution? heeeelp! Equation is H2C2O4 + 2NaOH==> 2H2O + Na2C2O4 I assume that is 25.00 mL H2C2O4. milliequivalents(meq) NaOH = meq H2C2O4 25 mL ...

thank you VERY much for your replies, DrBob. Another question, however: How many moles of ions -both cations and anions- are present in solution when 0.75 mol of potassium chloride is dissolved in 0.25L of distilled water? How do I work this answer to be: 1.5mol? KCl(s) + H2O...

I have a chemistry project where I need to make an object move using my knowledge of chemistry. The object os a small ball the size of a large marble. It must be moved using chemistry and NOT physics (ie slope wind etc). I am 15 and in grade 11.

could someone please answer my chemistry/stoichiometry questions below both "anonymous one just chemistry on todays date

I'm looking for a chemistry and applied chemistry textbook that had been published between 2011-2014. Please help because I couldn't find one on google.

At a certain college, 15% of the students receieved an A in their required math cousre, 10% receieved an A in their required chemistry course, and 5% receieved an A in both. A student is selected at random. a.) What is the probability that he received an A in either chemistry ...

Our professor just told us that the final exam will be the ACS exam, we are taking general Chemistry II. What is the best way to study for ir? Is the preparing for ACS general chemistry study guide good? If we are taking general Chemistry II do we have to study Chemistry I again?

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