Question

A sample of 7.70 L of NH3 (ammonia) gas at 22 ∘C and 735 torr is
bubbled into a 0.350 L solution of 0.400 *M* HCl
(hydrochloric acid).

The *K*b value for NH3 is 1.8×10−5.

Part A:

Assuming all the NH3 dissolves and that the volume of the solution remains at 0.350 L , calculate the pH of the resulting solution.

Answer #1

1st find the mol of NH3

Given:

P = 735.0 torr

= (735.0/760) atm

= 0.9671 atm

V = 7.7 L

T = 22.0 oC

= (22.0+273) K

= 295 K

find number of moles using:

P * V = n*R*T

0.9671 atm * 7.7 L = n * 0.08206 atm.L/mol.K * 295 K

n = 0.3076 mol

Given:

M(HCl) = 0.4 M

V(HCl) = 0.35 L

mol(HCl) = M(HCl) * V(HCl)

mol(HCl) = 0.4 M * 0.35 L = 0.14 mol

We have:

mol(HCl) = 0.14 mol

mol(NH3) = 0.3076 mol

0.14 mol of both will react

excess NH3 remaining = 0.1676 mol

Volume of Solution = 0.35 + 0 = 0.35 L

[NH3] = 0.1676 mol/0.35 L = 0.4789 M

[NH4+] = 0.14 mol/0.35 L = 0.4 M

They form basic buffer

base is NH3

conjugate acid is NH4+

Kb = 1.8*10^-5

pKb = - log (Kb)

= - log(1.8*10^-5)

= 4.745

use:

pOH = pKb + log {[conjugate acid]/[base]}

= 4.745+ log {0.4/0.4789}

= 4.667

use:

PH = 14 - pOH

= 14 - 4.6666

= 9.3334

Answer: 9.33

A sample of 7.50 L of NH3 (ammonia) gas at 22 ∘C and 735 torr is
bubbled into a 0.450 L solution of 0.400 M HCl (hydrochloric acid).
The Kb value for NH3 is 1.8×10−5.
Assuming all the NH3 dissolves and that the volume of the
solution remains at 0.450 L , calculate the pH of the resulting
solution.

A sample of 7.60 L of NH3 (ammonia) gas at 22 ∘C and 735 torr is
bubbled into a 0.450 L solution of 0.400 M HCl
(hydrochloric acid).
The Kb value for NH3 is 1.8×10−5.
Assuming all the NH3 dissolves and that the volume of the
solution remains at 0.450 L , calculate the pH of the resulting
solution. Express your answer numerically to two decimal
places.

A sample of 7.80 L of NH3 (ammonia) gas at 22 ∘C and 735 torr is
bubbled into a 0.450 L solution of 0.400 M HCl (hydrochloric acid).
The Kb value for NH3 is 1.8×10−5.
Assuming all the NH3 dissolves and that the volume of the
solution remains at 0.450 L , calculate the pH of the resulting
solution.
Express your answer numerically to two decimal places.
Thanks!

How many grams of dry NH4Cl need to be added to 1.80 L of a
0.400 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.

An 80.0 mL sample of 0.200 M ammonia is titrated with 0.100M
hydrochloric acid. Kb for ammonia is 1.8 x 10-5. Calculate the pH
of the solution at each of the following points of the titration:
a. before the addition of any HCl. ______________ b. halfway to the
equivalence point.______________ c. at the equivalence
point._________________ d. after the addition of 175 mL of 0.100M
HCl.____________

How many grams of dry NH4Cl need to be added to 1.80 L of a
0.400 M solution of ammonia, NH3, to prepare a buffer solution that
has a pH of 8.60? Kb for ammonia is 1.8×10−5. Express your answer
with the appropriate units.

17. A 25.0-mL sample of 0.20 M
NH3 is titrated with 0.20 M HCl. What is the pH
of the solution after 15.00 mL of acid have been added to the
ammonia solution? (NH3 has Kb = 1.8
x 10–5)
18. The Ksp of silver
chloride is 1.6 x 10–10. (a) Calculate
the molar solubility. (b) Dissolve 0.01 moles of
NaCl to 1.0 L of water; calculate the molar solubility of AgCl in
this salt water.

PART A
Ammonia, NH3, is a weak base with a Kb value of
1.8×10−5 and a pH of 11.27. What is the percent ionization of
ammonia at this concentration?
PART B
Write a chemical equation for Sr(OH)2(aq)
showing how it is an acid or a base according to the Arrhenius
definition.
PART C
Find the pH of the following solutions of
mixtures of acid: 0.155 M in HNO2 and 8.5×10−2 M in
HNO3

PART A
A buffer solution contains 0.358 M
ammonium chloride and
0.499 M ammonia.
If 0.0274 moles of perchloric
acid are added to 125 mL of this buffer,
what is the pH of the resulting solution ?
(Assume that the volume change does not change upon adding
perchloric acid)
pH = _______
PART B
A buffer solution contains 0.328 M
nitrous acid and 0.481 M
sodium nitrite.
If 0.0248 moles of hydrochloric
acid are added to 125 mL of this...

Ammonia, NH3, is a weak base with a Kb value of
1.8×10−5.
Part A
What is the pH of a 0.480 M ammonia solution?
Express your answer numerically to two decimal places.
Part B
What is the percent ionization of ammonia at this
concentration?
Express your answer with the appropriate units.

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 53 minutes ago

asked 1 hour ago

asked 2 hours ago

asked 2 hours ago

asked 2 hours ago

asked 2 hours ago

asked 3 hours ago

asked 3 hours ago

asked 3 hours ago

asked 3 hours ago

asked 3 hours ago

asked 3 hours ago