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April 16, 2014

Search: chem--buffers

Number of results: 14,319

Biology
http://www.brynmawr.edu/Acads/Chem/Chem104lc/buffers.html See the three classes here.
Saturday, January 12, 2008 at 9:03pm by bobpursley

Chem--buffers
thank you....i understand the concept clearly now.
Sunday, February 28, 2010 at 7:56pm by Rav

Chem--buffers
thank you....i understand the concept clearly now.
Sunday, February 28, 2010 at 7:56pm by Rav

Chem
.1 M HCl + .1 M NaCl .1 M HF + .1 M NaF .1 M HBr + .1 M NaBr Which of the above would be considered buffers?
Tuesday, April 22, 2008 at 10:35pm by Confused

biochemistry with more info that was needed
which buffer do I choose? There are instructions above the table does this have anything to do with my choice for the problem i am working out, or do I just pick whatever one I want and do the math? Above the table it states, Make two buffers starting with solid material, ...
Sunday, January 27, 2008 at 5:35pm by stew

science(chem)
I found the other site. Here it is. http://www.haverford.edu/chem/Scarrow/GenChem/acidbase/buffer_prep.html The usual biochemistry buffers means one thing and analytical chemists express buffers another way (or I may be out of touch with the new day thinking). At any rate, a 0...
Sunday, September 21, 2008 at 11:28pm by DrBob222

Chem Lab
I don't know how we can sue the NH3/NH4Cl system; however, the pKa for NH3 is 9.25 and that is within the range. What about the two buffers of 0.2M and 0.1M?
Wednesday, April 11, 2012 at 11:21pm by DrBob222

chem 2
Please don't change screen names. Buffers are most effective when the pKa is in the range of desired pH; and that means base/acid = 1 So you want to pick the NaC2H3O2 concn that gives the value closest to b/a = 1.
Saturday, March 3, 2012 at 1:55pm by DrBob222

Chemistry
3 buffers in the human body and what are their conjugate acid-base pairs? I have Bicarbonate Buffer, Phosphate/Ammonia Buffer, and Protein Buffers, where my confusion lies in what would be there conjugate acid base pairs.......
Saturday, November 12, 2011 at 4:21pm by Mandie

chemistry (buffers)
Buffers are combinations of a weak acid and a weak base, not a weak acid and a strong base.
Monday, September 1, 2008 at 3:15am by GK

Chem Lab
Can the NH3/NH4Cl system be sued to prepare a buffer of a pH 9.5? why or why not? Can it prepare a buffer of pH 5? There were two buffers, 0.2 M and 0.1M.
Wednesday, April 11, 2012 at 11:21pm by Logan

chem( buffers)
Does water have a high buffering capacity? Why is it important to know it buffering capacity of water?
Saturday, August 28, 2010 at 2:19am by lou

chemistry
Perhaps this will help. http://www.chemcollective.org/buffers/buffers5.php
Monday, January 30, 2012 at 6:04pm by DrBob222

Chemistry
An industrial chemist studying bleaching and sterilizing prepares several hypochlorite buffers. Find the pH of the following buffers. (a) 0.090 M HClO and 0.090 M NaClO (b) 0.090 M HClO and 0.135 M NaClO (c) 0.135 M HClO and 0.090 M NaClO (d) One liter of the solution in part...
Monday, March 4, 2013 at 8:53pm by Edward

biochemistry with more info that was needed
okay, let me just stick to the pre-lab question using the table. Here is the pre-lab question: Calculate the weight of the buffers you will use to make the buffers for part A for all the buffer possibilities listed under procedures in part A, stp i. In other words, how many ...
Sunday, January 27, 2008 at 5:35pm by stew

chem
Here is a site to read about buffers. Note the table of buffers. http://en.wikipedia.org/wiki/Buffer_solution Based on the link above, NaCN and HCN (1) would qualify as a buffer since it is a weak acid (HCN) and its conjugate base (CN^-). HCl and NaCN (4) will qualify in most ...
Sunday, April 10, 2011 at 7:19pm by DrBob222

chem
I don't believe 1 will do it. Yes on 5. Also 3. Buffers are weak acid and salt or weak base and salt. HCN and NaOH can prepare the salt and have HCN left over. NaCN is the salt HCN for the acid.
Saturday, April 9, 2011 at 2:27pm by DrBob222

biochemistry with more info that was needed
Calculate the weight of the buffers you will use to make the buffers for Part A for all the buffer possibilities listed under procedures in Part A, step 1. In other words, how many grams do you need to make 100 mL of a 0.1 M buffer? Buffer pKa1 pKa2 pKa3 formula wt.(g/mol) ...
Sunday, January 27, 2008 at 5:35pm by stew

Chemistry
Buffers are commonly at a neutral pH of 7; this is wrong. Buffers are usually equal to the pKa or pKb of the acid and its conjugate base, or the base and its conjugate acid. You are right: they do counter act the addition of an acid by by making more of its conjugate base, or ...
Thursday, March 14, 2013 at 2:20am by Devron

chem
Citric acid is the salt of a weak acid and a strong base. I would add citric acid, a weak acid. Buffers are weak acids and their salts or weak bases and their salts.
Thursday, February 7, 2008 at 1:12am by drbob222

buffers
You're welcome.
Wednesday, March 3, 2010 at 10:55pm by DrBob222

Chem--buffers
Explain why a mixture formed by mixing 100 mL of 0.100M CH3COOH and 50 mL of 0.100M NaOH will act as a buffer? in adittion to this, how do you identify if a an aqueous solution is a buffer solution, such as a solution with an acid and a base, but no common ion? is it possible ...
Sunday, February 28, 2010 at 7:56pm by Rav

chemistry
Buffer capacity can be defined in a variety of ways; the one I use is, "the mols of strong acid or strong base that can be added to 1 L of a buffer that will change the pH by 1 unit. You look at your graph and read the beginning pH and mols (say acid) then find the pH that is ...
Saturday, April 14, 2012 at 11:07am by DrBob222

buffers
thanks a lot :D
Wednesday, March 3, 2010 at 10:55pm by Reen

Chemistry
You KNOW #1 and #3 are buffers.
Sunday, April 10, 2011 at 7:16pm by DrBob222

Pharmaceutics?
Acids, bases, and buffers?
Monday, September 15, 2008 at 8:07pm by Ashley

buffers
we havn't learnt that equation.
Wednesday, March 3, 2010 at 10:55pm by Reen

buffers
thanks. so for this question is the pH 3.70?
Wednesday, March 3, 2010 at 10:55pm by Reen

Chemistry (repost)
Which of the following pairs of substances, when mixed in any proportion you wish, can be used to prepare a buffer solution? 1)NaCN and NaOH 2) HCl and NaOH 3) HCN and NaOH 4)HCl and NaCN 5) NaCN and HCN is the answer 1 and 5?? chem - DrBob222, Sunday, April 10, 2011 at 1:28am...
Sunday, April 10, 2011 at 4:16pm by Rachel

buffers
Use the Henderson-Hasselbalch equation.
Wednesday, March 3, 2010 at 10:55pm by DrBob222

chemistry
How do basic and acidic buffers resist pH ?
Thursday, September 23, 2010 at 10:54pm by CHELsea

Steph
Buffers work by converting _____ to ____.
Tuesday, November 1, 2011 at 10:38pm by Chemistry

chem--buffers
yes, that is exactly what i get(i got 5.87, but that's probably just a simple rounding error). i used the wrong equation, and didn't include the hydrogen ion from HCl in the equation, and just used the acetic ion as the only source of the hydroxide ion. But your process does ...
Sunday, March 7, 2010 at 5:02pm by Rav

Chemistry - buffers
Thank you very much for the help! Now I see what should I do.
Monday, March 26, 2012 at 2:39pm by Anonymous

Chemistry
Both of these are buffers. Use the Henderson-Hasselbalch equation.
Tuesday, May 1, 2012 at 5:02pm by DrBob222

buffers
I calculate 3.698 pH which rounds to 3.70. Yes. Very good.
Wednesday, March 3, 2010 at 10:55pm by DrBob222

chemistry
if there were no buffers in our blood, what would happen when we drank something acidic?
Thursday, July 14, 2011 at 12:37pm by ana

Chemistry- Buffers
Show me how you obtained pH = 4.74. I can't get that. My answer looked more like 4.79.
Sunday, December 5, 2010 at 9:53pm by DrBob222

Chemistry
Name 3 buffers that exist in the human body? Include the conjugate and acid base pairs
Friday, November 11, 2011 at 11:41pm by Monique

Chemistry - buffers
If that's all of it then your prof didn't give very good directions. I have no idea which acid he/she has in mind so I'll fly blind. I looked at the Ka values and picked HOCl. With pH = 8 for a buffer I might pick HOCl for the acid with Ka = 3.0E-8 (you need to see what that ...
Monday, March 26, 2012 at 2:39pm by DrBob222

biology
Duodenal glands secrete mucus that contains buffers, and water also enters and mixes with the chyme.
Wednesday, February 3, 2010 at 4:17pm by Anonymous

chemistry
1. Compare the effects of adding the strong acid & base to the pH of water vs. the acetate and phosphate buffers.
Wednesday, October 24, 2012 at 2:15pm by hi

chemistry
Buffers work because of the way they are constructed. Buffers consist of a weak acid and a salt of the weak acid. For example, HF for the weak acid and NaF as the salt. When a strong acid, such as HCl, is added, the multiple H^+ are used up by the salt to form more of the weak...
Friday, May 4, 2012 at 5:14pm by DrBob222

Chemistry (buffers)
See your other posts. Please don't change screen names. It takes us long to answer.
Thursday, March 15, 2012 at 7:30pm by DrBob222

Chem 2
A popular buffer solution consist of carbonate (CO3 2-) and hydrogen carbonate (HCO3-) conjugate acid-base pair. Which, if any of the following such buffers has the highest buffer capacity? A. 0.9M CO3 2- and 0.1M HCO3- B. 0.1M CO3 2- and 0.9M HCO3- C. 0.5M CO3 2- and 0.5M ...
Sunday, March 4, 2012 at 11:05pm by Debbie

Chemistry - buffers
This must be part of another series of questions since it refers to "same concentration solutions". As it stands we don't know the whole problem.
Monday, March 26, 2012 at 2:39pm by DrBob222

chem--buffers
Calculate [H30+] in a solution that is 0.0525M HCl and 0.768M NaC2H3O2. Ka(HC2H3O2)= 1.8 x10^-5. the way i did it is that i used the given molar of HCl to find the moles of Hydronium in the acid, and then i used that to find the moles of OH- in it, using kw. then thru the ...
Sunday, March 7, 2010 at 5:02pm by Rav

Chemistry -buffers.
**1 mole of CO2 at stp is 22.26L Pka=6.1 at 37C Solubility coefecient =0.031 mmol/LmmHg at 37 C
Sunday, November 6, 2011 at 12:14am by Maria

buffers
9.00mL of 1.10M CH3COOH and 1.00mL of 0.900M CH3COO- what is the pH?
Wednesday, March 3, 2010 at 10:55pm by Reen

Chemistry - buffers
No, it's all problem. Well the end is: search all constants in internet and books
Monday, March 26, 2012 at 2:39pm by Anonymous

Chemistry - buffers
Laborant got a task to make a buffer, which pH = 8.00. Which same concentration solutions and which ratio would you suggest him to mix?
Monday, March 26, 2012 at 2:39pm by Anonymous

Chemistry- Buffers
-log Ka = pKa which may or may not be = pH. Ka is a measure of how strong/weak the acid is.
Sunday, December 5, 2010 at 9:53pm by DrBob222

College Chemistry
Calculate the ratio of NaF to HF required to create a buffer with pH=3.95. Also, can you please explain in a nutshell the whole concept of buffers? Thanks!
Tuesday, March 23, 2010 at 10:44pm by Katie

chemistry - buffers
what mass of sodium acetate should be dissolved in 1.00L of acetic acid, 0.150M concentration, in order to produce a buffer with pH = 4.5?. Ka of CH3COOH = 1.8x10^-5
Monday, April 12, 2010 at 7:38pm by Reen

chemistry
Since amino acids and proteins carry proton-accepting and proton-donating groups, they can act as a.buffers b.enzymes c.isomers d.vitamins
Sunday, December 11, 2011 at 10:35am by anonymous

Buffer solution
is these buffers solution NH3, NaC2H3O2 NH3,NH4Cl HC2H3)2,HN)3 KOH,KCl
Saturday, March 27, 2010 at 7:34pm by shantel

Chemistry (buffers)
Say, for example, that you had prepared a Buffer C, in which you mixed 8.203 g of sodium acetate, NaC2H3O2, with 100.0 mL of 1.0 M acetic acid. a. What would be the initial pH of Buffer C? HOW???????
Thursday, March 15, 2012 at 7:30pm by James

electronics
Here we examine noise in a digital channel between an AND gate and an inverter shown in Figure 16. The channel has a length of D=30m and noise is added in at the rate of 0.6Vm. To correct for that noise, we introduce non-inverting buffers into the channel. The purpose of a ...
Sunday, August 24, 2008 at 10:40pm by AmmanJordan

bio chemistry
calculate the PH of each of the following buffers prepared by placing in 1.0 L of solution 0.10 mol NH3 and 0.10 mol of NH4CL
Friday, March 2, 2012 at 11:11am by samar

chem--buffers
I would be interested in the calculations you didn't show. If I understand what you did you have (H^+) 0.0525 and that makes the "initial" OH = 1.9 x 10^-13 which seems unreasonably high. I would approach it a little differently. I would start with HCl is a strong acid and the...
Sunday, March 7, 2010 at 5:02pm by DrBob222

chemistry
Which one of the following mixtures is suitable for making buffers? 1 H3PO4 and NaH2PO4 2 Na2CO3 and NaHCO3 3 NH4Cl and NH3 a. 1 only b. 2 only c. 3 only d. 1 and 2 only e. 1, 2, and 3
Thursday, May 13, 2010 at 5:43am by zacky

Electronics
Here we examine noise in a digital channel between an AND gate and an inverter shown in Figure 16. The channel has a length of D=30m and noise is added in at the rate of 0.6Vm. To correct for that noise, we introduce non-inverting buffers into the channel. The purpose of a ...
Friday, May 3, 2013 at 8:22am by AmmanJordan

Chemistry- Buffers
Since Ka a measure of H+ ions, -log(Ka)= pH.. my assignment says that part is right, I just don't know what to do from there to get M -> moles -> grams
Sunday, December 5, 2010 at 9:53pm by Mikey

Chemistry - buffers
Two burettes are filled with solutions: one with 0,1OM CH3COOH solution, second with 0,15M CH3COONa. How many milliliters each solution will need to make 20mL of solution, which pH=4.85
Monday, March 26, 2012 at 2:43pm by Anonymous

E.M.U
For the same solution components as in part (f), buffers are prepared with a total concentration of NH3 + NH4Cl = 0.10 M. The pH values are 8.0, 8.5, 9.0, 9.5, 10.0, 10.5, and 11.0. Find the molar solubility of CdS in these solutions
Wednesday, March 26, 2014 at 4:26pm by k.sina

chemistry
Buffers resist a change in pH. The DO change pH, however. They do not prevent a change from taking place.
Tuesday, April 8, 2008 at 9:43pm by DrBob222

chemistry
One thing to learn quickly in buffers is that when bae = acid(as in this case) is that pH = pKa. You know Ka so -log Ka = pKa = pH
Wednesday, December 5, 2012 at 11:29am by DrBob222

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

Science- Chemistry
How many grams of sodium acetate( molar mass 82.03 g/mol) must me added to 1.00L of a 0.200M acetic acid solution to form a buffer of 4.20?Ka value for aceic acid is 1.8 x 10^-5. How do I go about finding the grams from the given information? http://www.chembuddy.com/?left=pH-...
Saturday, June 2, 2007 at 4:31pm by Catherine

Chemistry- Buffers
a buffer is prepared by mixing .208 L of 0.452 M HCl and 0.5 L of 0.4 M sodium acetate. When the Ka= 1.8 x 10^-5 I figured out that the pH= 4.74 but then it asks how many grams of KOH must be added to the buffer to change the pH by .155 units?
Sunday, December 5, 2010 at 9:53pm by Mikey

Chemistry
Use the Henderson-Hasselbalch equation. That's what you use for buffers. pH = pKa + log (base)/(acid) The base is the K salt and the acid is propionic acid.
Thursday, March 21, 2013 at 9:20pm by DrBob222

Biology
I know that the phosphate [cells] and sodium barcarbonate [blood plasma] buffer systems are two examples of biological buffers; however, i am writing an essay for bio and i need a third example. does anyone know of a third biological buffer system?
Saturday, January 12, 2008 at 9:03pm by Jake

chemistry
Buffers are a weak acid and one of its salts or a weak base and one of its salts.
Thursday, May 13, 2010 at 5:43am by DrBob222

Chemistry - buffers
Use the Henderson-Hasselbalch equation. I would set base = millimols base = mLB*0.15. mmols acid = mLA(0.1M) = (20-mLB)*0.1 Substitute and solve for mLB, then mLA.
Monday, March 26, 2012 at 2:43pm by DrBob222

chemistry
I don't understand it either. You appear to have typed part of a line twice. If that extra 6M NH3 (equal volume added) is part of the question, the solution forms Pb(OH)4^2- from Pb(OH)2, Cu(OH)4^2- (from Cu(OH)2), and those could act as buffers.
Wednesday, November 7, 2012 at 12:35pm by DrBob222

Biochem
HEPES, is a commonly used component of physiological buffers. The PKa of the protonated amino group of HEPES is 7.55 at 25C. Describe the preparation of 1.00L of 0.100M HEPES buffer, pH 8.00, from the sodium salt of the basic form of HEPES (MW 260.3), .0M HCL and deionized water
Monday, September 13, 2010 at 10:50pm by Angel

Chemistry
A good buffer consists of a weak acid and its salt OR a weak base and its salt. For example, a is not a good buffer while b is. There are others in your list that are good buffers.
Saturday, February 26, 2011 at 3:06pm by DrBob222

Biochemistry
Sorry! HEPES, is a commonly used component of physiological buffers. The PKa of the protonated amino group of HEPES is 7.55 at 25C. Describe the preparation of 1.00L of 0.100M HEPES buffer, pH 8.00, from the sodium salt of the basic form of HEPES (MW 260.3), 6.0M HCl and ...
Tuesday, September 14, 2010 at 10:48pm by Angel

Chemistry -buffers.
The pH of an arterial blood sample is 7.15. upon acidification of 10 ml of the plasma 5.91ml of CO2 is produced at standard temperature and presure. Calculate-a) total CO2 in the specimen b)the individual concentration of disolved CO2(H2CO3) and HCO3- c)The partial pressure of...
Sunday, November 6, 2011 at 12:14am by Maria

chemistry buffers
What molar ratio of HPO4 2- to H2PO4 - in solution would produce a pH of 7.0? Phosphoric acid (H3PO4), a triprotonic acid, has pKa values: 2.14, 6.86, and 12.4. Only one of the pKa values is relevant here. how do i know which pka value to use.. please explain
Sunday, September 9, 2012 at 4:28pm by ron

Biochemistry
Dr. Bob222 is correct, you will need to add base to increase the pH of HEPES to 8, since the pKA of the solution is at 7.5. Remember, buffers have equal concentrations of its acid and conjugate base. Therefore, the pH of the solution is equal to the pKa.
Wednesday, January 30, 2013 at 9:49pm by Devron

chemistry (buffers)
How can weak acid nitrous acid HNO2 form a buffer solution with equal concentrations and volumes with weak base NH3? I thought that buffer solutions only occured between weak acids and strong bases or vice versa. The example above as two weak soltuions.
Monday, September 1, 2008 at 3:15am by mike

Biology(Anatomy&Physiology)
1)Which group of organic molecules makes up your genetic code 2)A substance which tends to resist a change in the pH of a solution is called a 3)Which buffers is the most common in the body 4)Which of molecules is primarily made of CHON 5)Which is the building block or monomer...
Wednesday, October 15, 2008 at 8:30pm by Stephanie

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

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 organic chem
Responded above to a later repost.
Tuesday, November 13, 2007 at 6:18pm by DrBob222

gen chem
i tried that, apparently its not the right answer either =/.
Saturday, May 8, 2010 at 7:46pm by Chem

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

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

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 ):

Science
Describe the procedure for preparing 250mL of buffer solution with a pH of 5.00 from acetic acid (CH3COOH) and sodium acetate. How many grams of acid do you have to mix with 3.6 grams of sodium acetate? (Given Ka for acetic acid = 1.8x10^-5)
Monday, October 25, 2010 at 12:29am by Chemisty-Buffers

Chem
maybe try using P1V1/n1T1 = P2V2/n2T2 ... im in chem too...
Saturday, February 27, 2010 at 1:16am by fellow student

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

G-chem/org. chem=>Dr. Bob222
I mean are setups differ for part 1
Friday, February 8, 2013 at 5:58pm by Devron

chem help
sorry the 2nd question is the right one
Saturday, February 28, 2009 at 11:56pm 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

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

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

chem
sorry read it wrong, doing this now in chem
Tuesday, March 19, 2013 at 6:02pm by Amanda

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