Question

In: Chemistry

What mass of ammonium chloride should be added to 2.60 L of a 0.145 M NH3...

What mass of ammonium chloride should be added to 2.60 L of a 0.145 M NH3 in order to obtain a buffer with a pH of 9.45?

Solutions

Expert Solution

The pH of buffer is calculated using Hendersen Hassalbalch's equation. For basic buffer the equaiton is

pOH = pKb + log [salt] / [base]

Or

pH = pKa + log [base] / [salt]

Moles of base = Molarity X volume = 0.145 X 2.60 = 0.377 moles

pKa = 14 - pKb

Kb = 1.8 X 10−5   therefire pKb = -logKb = 4.745

pKa = 14- 4.745 = 9.255

pH = 9.45

pH = 9.45 = 9.255 + log [0.377 / [salt]

0.195 = log [0.377 / [salt]

Taking antilog

1.57 = 0.377 / [ salt]

[salt] = moles of salt = 0.2401

mass of salt (NH4Cl) = moles X molecular weight of NH4Cl

Molecular weight of NH4Cl = 53.5 g / mole

Mass of salt (NH4Cl0 = 0.2401 X 53.5= 12.85 grams


Related Solutions

What mass of ammonium chloride should be added to 2.50 L of a 0.145 M NH3...
What mass of ammonium chloride should be added to 2.50 L of a 0.145 M NH3 in order to obtain a buffer with a pH of 9.65?
What mass of ammonium chloride should be added to 2.55 L of a 0.150 M NH3...
What mass of ammonium chloride should be added to 2.55 L of a 0.150 M NH3 in order to obtain a buffer with a pH of 9.60?
What mass of ammonium chloride should be added to 2.45 L of a 0.165 M NH3...
What mass of ammonium chloride should be added to 2.45 L of a 0.165 M NH3 in order to obtain a buffer with a pH of 9.65?
How many grams of solid ammonium chloride should be added to 1.50 L of a 0.145...
How many grams of solid ammonium chloride should be added to 1.50 L of a 0.145 M ammonia solution to prepare a buffer with a pH of 10.190 ?
1) How many grams of solid ammonium chloride should be added to 1.50 L of a...
1) How many grams of solid ammonium chloride should be added to 1.50 L of a 0.273 M ammonia solution to prepare a buffer with a pH of 8.540 ? 2) How many grams of solid sodium hypochlorite should be added to 1.00 L of a 0.239 M hypochlorous acid solution to prepare a buffer with a pH of 8.109 ?
What mass of ammonium nitrate must be added to 350 mL of a 0.150 M solution...
What mass of ammonium nitrate must be added to 350 mL of a 0.150 M solution of ammonia to give a buffer having a pH of 9.00. (kb(NH3)=1.8x10^-5). please show each step in detail.
Solid ammonium chloride, NH4Cl, is formed by the reaction of gaseous ammonia, NH3, and hydrogen chloride,...
Solid ammonium chloride, NH4Cl, is formed by the reaction of gaseous ammonia, NH3, and hydrogen chloride, HCl.NH3(g)+HCl(g)⟶NH4Cl(s) A 6.37 g sample of NH3 gas and a 6.37 g sample of HCl gas are mixed in a 1.00 L flask at 25 ∘C. How many grams of NH4Cl will be formed by this reaction? What is the pressure in atmospheres of the gas remaining in the flask? Ignore the volume of solid NH4Cl produced by the reaction.
What mass of NH4Cl must be added to 250.0 mL of 0.200 M NH3 solution to...
What mass of NH4Cl must be added to 250.0 mL of 0.200 M NH3 solution to have a buffer solution at pH=8.90? Assume no volume change. A 15.0-mL sample of a H3PO4 solution is titrated with a 1.00 M NaOH solution. The neutralization reaction is complete when 33.6 mL of NaOH is added. What is the concentration of the H3PO4 solution (in M)?
How many grams of ammonium chloride, NH4Cl, must be added to 500 ml of 0.10 M...
How many grams of ammonium chloride, NH4Cl, must be added to 500 ml of 0.10 M NH3 solution to give a solution with a pH of 9.0?
Calculate the mass of ammonium chloride required to prepare 25 mL of a 2.0 M solution,...
Calculate the mass of ammonium chloride required to prepare 25 mL of a 2.0 M solution, and the mass of calcium chloride required to prepare 25 mL of a 2.0 M solution.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT