You are asked to prepare 2.3 L of a HCN/NaCNbuffer that has a pH of 9.63 and an osmotic pressure of 1.30 atm at 298 K.
What masses of HCN and NaCN should you use to prepare the buffer? (Assume complete dissociation of NaCN.
Answer:
Given,
To determine the masses of HCN and NaCN
Consider,
Concentration of buffer = P/RT
Substitute the known values in above expression
= (1.30/(0.0821*298))
= 0.05314 M
No of moles of buffer = 0.05314*2.3
= 0.1222 mol
Now,
pH = pka + log(salt/acid)
9.63 = 9.2 + log(x/(0.1222-x))
By solving we get
x = No of mol of NaCN = 0.0891 mol
No of mol of HCN = 0.1222 - 0.0891
= 0.0331 mol
mass of NaCN = 49*0.0891
mass of NaCN = 4.3659 grams
mass of HCN = 0.0331*27
mass of HCN= 0.8937 grams
You are asked to prepare 2.3 L of a HCN/NaCNbuffer that has a pH of 9.63...
You are asked to prepare 2.9 L of a HCN/NaCN buffer that has a pH of 9.79 and an osmotic pressure of 1.79 atm at 298 K. What masses of HCN and NaCN should you use to prepare the buffer? (Assume complete dissociation of NaCN.)
You are asked to prepare 1.0 L of a HCN/NaCN buffer that has a pH of 9.86 and an osmotic pressure of 1.97 atm at 298 K. What masses of HCN and NaCN should you use to prepare the buffer? (Assume complete dissociation of NaCN.)
You are asked to prepare 3.8 L of a HCN/NaCN buffer that has a pH of 9.62 and an osmotic pressure of 1.39 atm at 298 K. What masses of HCN and NaCN should you use to prepare the buffer? (Assume complete dissociation of NaCN.)
You are asked to prepare 4.0 L of a HCN/NaCN buffer that has a pH of 9.62 and an osmotic pressure of 1.45 atm at 298 K. Part A What masses of HCN and NaCN should you use to prepare the buffer? (Assume complete dissociation of NaCN.) Express your answers using two significant figures separated by a comma.
18. You are asked to prepare a pH = 8.60 buffer starting from 500 mL of 0.10 M solution of hydrocyanic acid, HCN, and excess sodium cyanide, NACN. (Ka for HCN = 4.9 x 10-10) a) What is the pH of the hydrocyanic acid solution prior to adding NACN? b) How many grams of NaCN should be added to prepare the buffer solution?
Showing work, please answer questions a and b, thank you! You are asked to prepare a pH 8.60 buffer starting from 500 mL of 0.10 M solution of hydrocyanic acid, HCN, and excess sodium cyanide, NaCN. (Ka for HCN 4.9 x 10) 18. What is the pH of the hydrocyanic acid solution prior to adding NaCN? a) b) How many grams of NaCN should be added to prepare the buffer solution?
Question 64 of 68 What ratio of NaCN to HCN is needed to prepare a pH 9.80 buffer? (Ka of HCN is 4.9 x 10) 4 5 6 7 8 9 +/- : 0 x 100
Problem 1. You are asked to prepare a pH = 10.7 buffer starting from 517 mL of water to which 18.78 of ammonia have been added. The buffer will be prepared by the addition of ammonium chloride. fammonia add to water is 1.90x105. Assume that the volume does not change on the addition of ammonia or ammonium chloride. (a) Write the balanced net ionic equation for ammonia added to water. (b) What is the pH of the initial ammonia solution?...
You are asked to prepare a pH=4.00 buffer starting from 1.50 L of 0.0200M solution of benzoic acid (C6H5COOH) and an excess of sodium benzoate (C6H5COONa). How many grams of sodium benzoate should be added to prepare the buffer? Neglect the small volume change that occurs when the sodium benzoate is added.
You work in a chemistry lab, and are asked to prepare 500 mL of a buffer solution with pH-3.20, The weak acid solution concentration in this buffer should be 0.250 M and salt is a solid. The following steps walk you through a step by step process of this preparation. a. Choose the proper weak acids for the buffer solution Table 1. Ionization constant Ka for some weak acids Name Hydrofluoric acid Nitrous acid Fulminic acid Acetic acid Hypochlorous acid...