Question

In: Chemistry

How many grams of dry NH4Cl need to be added to 2.40 L of a 0.300...

How many grams of dry NH4Cl need to be added to 2.40 L of a 0.300 M solution of ammonia, NH3, to prepare a buffer solution that has a pH of 8.65? Kb for ammonia is 1.8×10−5.

Solutions

Expert Solution

no of moles of NH3 = molarity * volume in L

                                  = 0.3*2.4   = 0.72 moles

PH = 8.65

POH = 14-PH

           = 14-8.65    = 5.35

Kb    = 1.8*10^-5

PKb   = -logKb

          = -log1.8*10^-5

           = 4.75

POH   = Pkb + log[NH4Cl]/[NH3]

5.35   = 4.75 + log[NH4Cl]/0.72

5.35-4.75   = log[NH4Cl]/0.72

log[NH4Cl]/0.72   = 0.6

[NH4Cl]/0.72         = 10^0.6

[NH4Cl]/0.72         = 3.981

[NH4Cl]                 = 3.981*0.72   = 2.866

no of moles of NH4Cl   = 2.866

mass of NH4Cl            = no of moles * gram molar mass

                                    = 2.866*53.5   = 153.33g of NH4Cl >>>>>answer


Related Solutions

1) How many grams of dry NH4Cl need to be added to 2.40 L of a...
1) How many grams of dry NH4Cl need to be added to 2.40 L of a 0.800 M solution of ammonia, NH3, to prepare a buffer solution that has a pH of 8.82? Kb for ammonia is 1.8 x 10^-5. 2) A beaker with 150 mL of an acetic acid buffer with a pH of 5.000 is sitting on a benchtop. The total molarity of acid and conjugate base in this buffer is 0.100 M. A student adds 6.80 mL...
Part B How many grams of dry NH4Cl need to be added to 2.40 L of...
Part B How many grams of dry NH4Cl need to be added to 2.40 L of a 0.800 M solution of ammonia, NH3, to prepare a buffer solution that has a pH of 8.66? Kb for ammonia is 1.8×10−5. Express your answer with the appropriate units. mass of NH4Cl = ?
How many grams of dry NH4Cl need to be added to 1.70 L of a 0.700...
How many grams of dry NH4Cl need to be added to 1.70 L of a 0.700 M solution of ammonia, NH3 , to prepare a buffer solution that has a pH of 8.83? Kb for ammonia is 1.8×10−5 .
How many grams of dry NH4Cl need to be added to 2.00 L of a 0.100...
How many grams of dry NH4Cl need to be added to 2.00 L of a 0.100 M solution of ammonia, NH3, to prepare a buffer solution that has a pH of 8.53? Kb for ammonia is 1.8×10−5.
How many grams of dry NH4Cl need to be added to 2.10 L of a 0.400...
How many grams of dry NH4Cl need to be added to 2.10 L of a 0.400 M solution of ammonia, NH3, to prepare a buffer solution that has a pH of 8.58? Kb for ammonia is 1.8×10−5. Express your answer with the appropriate units.
How many grams of dry NH4Cl need to be added to 1.80 L of a 0.600...
How many grams of dry NH4Cl need to be added to 1.80 L of a 0.600 M solution of ammonia, NH3, to prepare a buffer solution that has a pH of 8.96? Kb for ammonia is 1.8×10−5
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?
a) How many grams of solid potassium cyanide should be added to 1.00 L of a...
a) How many grams of solid potassium cyanide should be added to 1.00 L of a 0.158 M hydrocyanic acid solution to prepare a buffer with a pH of 8.688 ? b) How many grams of solid ammonium chloride should be added to 2.00 L of a 0.171 M ammonia solution to prepare a buffer with a pH of 9.940 ?   c) Design a buffer that has a pH of 7.98 using one of the weak acid/conjugate base systems shown...
A) How many grams of solid sodium fluoride should be added to 2.00 L of a...
A) How many grams of solid sodium fluoride should be added to 2.00 L of a 0.190 M hydrofluoric acid solution to prepare a buffer with a pH of 2.425 ? grams sodium fluoride = g. B)   How many grams of solid sodium fluoride should be added to 1.00 L of a 0.299 M hydrofluoric acid solution to prepare a buffer with a pH of 3.825 ? grams sodium fluoride = g. C) How many grams of solid ammonium bromide...
A) How many grams of solid sodium fluoride should be added to 1.00 L of a...
A) How many grams of solid sodium fluoride should be added to 1.00 L of a 0.218 M hydrofluoric acid solution to prepare a buffer with a pH of 3.847 ? grams sodium fluoride =  g. B)How many grams of solid sodium hypochlorite should be added to 0.500 L of a 0.297 M hypochlorous acid solution to prepare a buffer with a pH of6.803 ? grams sodium hypochlorite =  g. C)How many grams of solid ammonium chloride should be added to 1.50...
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT