Homework Answers
![[Nah, poy]=20MM PH= 6.42 [Na₂HPou] = ? pka = 6.82 The equilibrium between two forms can be shown as;](http://img.homeworklib.com/questions/e0cc7660-1331-11ea-a634-cb65cafa5e2d.png?x-oss-process=image/resize,w_560)
![Na H₂poy - Na, Hpoy tht (Acid) (Salt) pH = pka + log [sall] [Acid 6.42= 6.82 + log x) 1 2 = 7.962mM7 Thus [Ngh Pow] = 7.962mM](http://img.homeworklib.com/questions/e18be680-1331-11ea-980e-894ebf7b3313.png?x-oss-process=image/resize,w_560)
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If you have a 20mM solution of NaH2PO4 and you want to make a solution of pH=6.42, what should be the concentratio...
a) What are the concentrations of Na2HPO4 and NaH2PO4 in a 0.30 M phosphate buffer solution...
a) What are the concentrations of Na2HPO4 and NaH2PO4 in a 0.30 M phosphate buffer solution pH 7.0? Use pKa 6.82 b) Describe how you would prepare 250 mL of the buffer in part (a) given that you have available to you a 1.0 M stock solution of NaH2PO4 and solid Na2HPO4(FW 141.96 g/mol). Provide your answer in milliliters of NaH2PO4 and grams of Na2HPO4. c) Suppose you use 100 ml of this buffer in an experiment and 0.003 mol...
1) Solution Components A 1 mL 100 mM NaH2PO4 + 9 mL 100 mM Na2HPO4 B...
1) Solution Components A 1 mL 100 mM NaH2PO4 + 9 mL 100 mM Na2HPO4 B 5 mL 100 mM NaH2PO4 + 5 mL 100 mM Na2HPO4 C 9 mL 100 mM NaH2PO4 + 1 mL 100 mM Na2HPO4 D 10 mL 100 mM NaH2PO4 stock solution E 10 mL 100 mM Na2HPO4 stock solution F 10 mL distilled water pKa of phosphate: 6.8 How would you calculate the pH of each equation using the Henderson Hasselbalch equations? 2) Tris...
You want to make 50mL of an aqueous solution containing 0.25 M of NaH2PO4. The MW...
You want to make 50mL of an aqueous solution containing 0.25 M of NaH2PO4. The MW of Na2PO4 is 119.98. To make this solution, how much NaH2PO4 would you add?
Goal- to make a 1L solution of phosphate buffer at pH 7.8 If you make up...
Goal- to make a 1L solution of phosphate buffer at pH 7.8 If you make up a 1M aqueous solution each of: NaH2PO4 and Na2HPO4 How much of each solution would you need to add (mix) to make up a 1 liter solution of 0.4 M phosphate at pH 7.8 Hint: the pKa for H2PO4- <-> HPO4 2- + H+ is 6.8)
4. If you want to make a buffer of 4.5 pH, how many grams of NaF...
4. If you want to make a buffer of 4.5 pH, how many grams of NaF do you need to add to 300 mL of 0.4 M HF solution? (Ka=7.1x10-4) Answer: 114.66 grams Pka -log (7.1 X10-4) = 3.1487411651 234
Buffer Practice 1.) You wish to prepare 750 mL of a buffer solution of pH =...
Buffer Practice 1.) You wish to prepare 750 mL of a buffer solution of pH = 7.00 and you decide to use NaH2PO4 as the acid, K2 = 6.2 x 10. You have on hand a 0.175 M solution of this acid. Kai = 7.5 x 103, Ka2 = 6.2 x 10-8, K3 = 4.2 x 10-13 a.) Calculate the pH of the NaH2PO4 solution. b.) Calculate the grams of Na2HPO4 that need to be added to 750 mL of...
1. You have a 1L solution of 0.1 M phosphate buffer at pH 2.0. What is...
1. You have a 1L solution of 0.1 M phosphate buffer at pH 2.0. What is the pH of this solution after you add 5 grams of NaOH? Assume there is no volume change and phosphate buffer has the following pKa values: 2.15, 6.82 and 12.38.
You are asked to prepare 500 ml of a 0 250 M acetate Puffer at pH...
You are asked to prepare 500 ml of a 0 250 M acetate Puffer at pH 5.00 using only pure acetic acid (MW = 60.05 g/mol, pKa = 4.76). 3 00 M NaOH, water. Answer the following questions regarding the preparation of the buffer. How many grams of acetic acid will you need to prepare the 500 mL buffer? Note that the given concentration of acetate refers to the concentration of all acetate species in solution. What volume of 3.00...
Henderson-Hasselbach equation: pH- pKa log (IA-|/IHA]) 1. Phosphate buffer is a mixture of KH2PO4 and K2HPO4....
Henderson-Hasselbach equation: pH- pKa log (IA-|/IHA]) 1. Phosphate buffer is a mixture of KH2PO4 and K2HPO4. Note that KH2PO4 has one additional proton. The pKa of the acid is 6.8. Use the Henderson-Hasselbach equation (above) to calculate the ratio of [K2HPO41[KH2PO4] needed to make a solution that is pH 7.2 2. To make a solution that is 0.2 M phosphate, the concentration of KH2PO4 and K2HPO4 must add up to 0.2 M. Use the ratio you calculated above, and the...
12. You are asked to prepare 500. mL of a 0.200 M acetate buffer at pH...
12. You are asked to prepare 500. mL of a 0.200 M acetate buffer at pH 4.90 using only pure acetic acid (MW=60.05 g/mol, pKa=4.76), 3.00 M NaOH, and water. Answer the following questions regarding the preparation of the buffer. a) How many grams of acetic acid will you need to prepare the 500 mL buffer? Note that the given concentration of acetate refers to the concentration of all acetate species in solution. g=? B) What volume of 3.00 M...
4. If you want to make a buffer of 4.5 pH, how many grams of NaF do you need to add to 300 mL of 0.4 M HF solution? (Ka=7.1x10-4) Answer: 114.66 grams Pka -log (7.1 X10-4) = 3.1487411651 234
Buffer Practice 1.) You wish to prepare 750 mL of a buffer solution of pH = 7.00 and you decide to use NaH2PO4 as the acid, K2 = 6.2 x 10. You have on hand a 0.175 M solution of this acid. Kai = 7.5 x 103, Ka2 = 6.2 x 10-8, K3 = 4.2 x 10-13 a.) Calculate the pH of the NaH2PO4 solution. b.) Calculate the grams of Na2HPO4 that need to be added to 750 mL of...
You are asked to prepare 500 ml of a 0 250 M acetate Puffer at pH 5.00 using only pure acetic acid (MW = 60.05 g/mol, pKa = 4.76). 3 00 M NaOH, water. Answer the following questions regarding the preparation of the buffer. How many grams of acetic acid will you need to prepare the 500 mL buffer? Note that the given concentration of acetate refers to the concentration of all acetate species in solution. What volume of 3.00...
Henderson-Hasselbach equation: pH- pKa log (IA-|/IHA]) 1. Phosphate buffer is a mixture of KH2PO4 and K2HPO4. Note that KH2PO4 has one additional proton. The pKa of the acid is 6.8. Use the Henderson-Hasselbach equation (above) to calculate the ratio of [K2HPO41[KH2PO4] needed to make a solution that is pH 7.2 2. To make a solution that is 0.2 M phosphate, the concentration of KH2PO4 and K2HPO4 must add up to 0.2 M. Use the ratio you calculated above, and the...
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