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What mass of sodium benzoate should be added to 160.0 mL of a 0.15 mL benzoic acid solution in order get a buffer with a pH of 4.30?
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∙ 10y ago
4.5 grams
Wiki User
∙ 10y ago
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How do you prepare 20 mM citrate phosphate buffer of PH 7?
10ml of 0.4M Citric acis solution 90 ml of 0.4M sodium phsophate dibasic solution 12.22g NaCl (tomake 150mM ionic solution) or 6.38g to make 100mM ionic strength. make up volume upto 2000ml with water. You should not need to pH this buffer . :)
How much Benzoic acid is in Mello Yello?
In regular Mello Yello there is no benzoic acid. There may be in diet or other variations of the brand. In order to find out how much is in it you will need to contact Coca-Cola. There should be a contact number on the product.
How do you prepare phosphate buffer solution of pH 8?
See the Web Links to the left of this answer.I especially like the Smith.edu link -- it has complete and very useful description of how to prepare a buffer.Use the Henderson-Hasselbach equation:pH = pKa + log [A-]/[HA]where HA is the protonated form of the weak acid, A- is the salt (dissociated acid, or in other words, its conjugate base), and the pKa is the strength of the acid.What this says is that the pH that you want your buffer to be depends on two things:-- the pKa of the weak acid you are using (see reference tables under the Web Links to the left)-- and the RATIO of the concentration of the acid and the salt that you add to the solution.The pH of the buffer does not depend on the actual concentration of the buffer, but on the ratio of the two parts.The buffer capacity depends on two things -- how close to the pKa the pH of the buffer actually is (it should be within 1-2 pH units), and what the total concentration of the buffer is.For instance if you have 0.001 M acetic acid and 0.001 M sodium acetate, the resulting buffer will have the exact same pH as a buffer made with 0.1 M acetic acid and 0.1 M sodium acetate (because the ratio is 1 to 1, the pH = pKa = 4.76). However, the 0.1 M buffer will have a much larger buffer capacity, and will much better resist changes in pH upon the addition of a strong acid or base.
Write the complete ionic equation for the reaction that occurs when a few drops of potassium hydroxide solution are added to the buffer?
NH4+ + Cl- + K+ + OH- --> NH3 + H2O + Cl- + K+ Since the question is not asking for the net ionic equation, spectator ions should be included in the ionic equation as well.
Effective pH range for sodium phosphate buffer of the pka value 2.15?
The effective range should be the pKa +/- 1. Therefore, the range should be 1.15 to 3.15.
What are pH electrode storage solution and pH 7.0 buffer and for what are they used?
The buffer solution is used to calibrate the meter. Usually two buffer solutions are used to do this. One is close to the range of the sample that will be measured, like the 7.0 buffer that you mention could be used for aquarium water. The other solution would be more acidic, like a 4.0 buffer solution. The process is to calibrate in one solution, rinse the probe, then calibrate in the other solution. This back and forth is done until the meter is reading the desired buffer and is stable. In other words, you would finish with the 7.0 buffer solution when it is reading exactly 7.0 PH, with no further adjustments after switching from the 4.0 solution. The probe should be rinsed with PH neutral DI water and shaken dry between each between each measurement so that solutions are not mixed. The storage solution is used to store the glass probe for long periods of time. A few drops of storage solution should be dripped into the probe cap before replacing it for storage. The storage solution is just a buffer that has some anti-bacterial additives to keep stuff from growing in it. The calibration buffer can be used for short term storage though. The glass probe should NEVER be allowed to dry out for long periods and should be rinsed with DI water before storage. It should NOT be stored in DI water though. Only buffer solution or storage solution should be used.
How do you separate benzoic acid from a mixture of CONGO RED and salt?
Dissolve the mixture in an apolar organic solvent, such as diethyl ether, and extract the acid with the addition of NaOH. The bezoic acid with ionize and go into the aqueous solution. Separate the two layers and add HCl to the aqueous layer to precipitate the benzoic acid. Wash the remaing ether solution with water and dry it with an anhydrous salt. Filter the ether solution and then remove the ether, the solvent, in order to obtain the pure benzoin.
How much water should be used for the recrystallisation of benzoic acid?
depends on how much benzoic acid you use. if you have 0.5g of benzoic acid , you need 30ml of water as a solvent.
How do you convert 1x buffer to 10x buffer?
The stocks are commonly labeled as X factors such as 10X, 5X, 100X etc. X-factor indicates that the solution is concentrated and must be diluted usually with water to 1X concentration for use. For eg: - A 100X concentrated solution should be diluted to 100 fold. to convert 1X to 10X take one ml of 1x buffer in a measuring cylinder and dilute it to make it 10 ml. its now 10x buffer.
How do you prepare 20 mM citrate phosphate buffer of PH 7?
10ml of 0.4M Citric acis solution 90 ml of 0.4M sodium phsophate dibasic solution 12.22g NaCl (tomake 150mM ionic solution) or 6.38g to make 100mM ionic strength. make up volume upto 2000ml with water. You should not need to pH this buffer . :)
What is meant by pinned buffer in comptuer organization?
due to some reasons, a buffer that should not be replaced is called pinned buffer
When preserving how much sodium benzoate should you use?
I's recommended to use about 0.1% of the total weight you get in your product. For example, if you get 150 kilograms of marmalade, use 15 grams of sodium benzoate.
How much Benzoic acid is in Mello Yello?
In regular Mello Yello there is no benzoic acid. There may be in diet or other variations of the brand. In order to find out how much is in it you will need to contact Coca-Cola. There should be a contact number on the product.
What happens to bicarbonate buffer system during dehydration and hydration?
Hi, This situation should be avioded, as buffer requires excess water to be effective. Rob.
What is the process of purification?
It simply means, isolating a chemical so there are no other compounds present with in the mixture other than just the one you want. E.g. C6H5COONa(aq) + HCl(aq) --> C6H5COOH(s) + NaCl(aq). To make pure benzoic acid you would neeed to use the purification process known as recrystalisation. The precipitate formed in this reaction would not be pure, it would contain some unreacted sodium benzoate and some undissolved sodium chloride along with any other original impurities.. Benzenoic acid is not soluble in cold water but is completely soluble in hot water (95`C). First dissolve benzoic acid completely in hot water, then cool and allow the ppt to form, this should be almost pure benzoic acid, the more times you recrystalise the more pure the sample, however % yield does decrease.
What is a buffer solution and how is it used?
A buffer solution is an aqueous solution that consists of a mixture of a weak acid and its conjugate base or a weak base and its conjugate acid. It is used to run biochemical assays; to prevent changes in the pH of a solution.
Is buffer capacity the same if determined by titration with a strong base instead of a strong acid?
It depends a bit on the buffer itself, but it is usually true. Generally speaking, a buffer is a solution composed of a weak acid (or base) along with its conjugate base (or acid). Usually, the two components (let's call the HA and A- for a weak acid and its conjugate base) are added in equal concentrations. If this is the case, then it is also true that the pH of the solution is equal to the pKa of the weak acid, a very useful fact. If the concentration of two HA and A- are equal, then the buffer capacity should be the same using a strong acid or strong base. However, you can also make a buffer with unequal concentrations of HA and A-. This is still considered a buffer solution, and it will resist change to pH in both directions, but unequally now. If you have a higher concentration of HA than A-, then the buffer will have a higher capacity to resist pH change if you add a strong base (because the base will be deprotonating HA, which you have more of). If you added a strong acid instead, then you would protonate all the A- faster (than you would deprotonate HA with the same amount of strong base), and so it would have a lower buffer capacity. This discussion works equally well if you are using a weak base (B) and its conjugate acid (HB+) instead, except everything is switched!
