Question

1. How many grams of sodium lactate, NaC3H5O3, should be
added to 1.00 L of 0.150 M lactic acid, HC3H5O3, to form a buffer
solution with a pH of 3.90? (Ka = 1.4*10^-4 for lactic acid)

How do you do this?

Answer #1

Ka = 1.4*10^-4

pKa = - log (Ka)

= - log(1.4*10^-4)

= 3.8539

use formula for buffer

pH = pKa + log ([NaC3H5O3]/[HC3H5O3])

3.9 = 3.8539 + log ([NaC3H5O3]/[HC3H5O3])

log ([NaC3H5O3]/[HC3H5O3]) = 0.0461

[NaC3H5O3]/[HC3H5O3] = 1.1121

[NaC3H5O3] = 0.1668

volume , V = 1.0 L

we have below equation to be used:

number of mol,

n = Molarity * Volume

= 0.1668*1

= 0.1668 mol

Molar mass of NaC3H5O3 = 1*MM(Na) + 3*MM(C) + 5*MM(H) + 3*MM(O)

= 1*22.99 + 3*12.01 + 5*1.008 + 3*16.0

= 112.06 g/mol

we have below equation to be used:

mass of NaC3H5O3,

m = number of mol * molar mass

= 0.1668 mol * 112.06 g/mol

= 18.7 g

Answer: 18.7 g

a. How many grams of sodium lactate, NaC3H5O3 should be added to
1.00L of 0.150M lactic acid, HC3H5O3 to form a buffer solution with
a pH of 3.90? (Ka= 1.4 x 10^-4 for lactic acid)
b. What is the pH of the buffer solution containing 0.10moles of
acetic acid and 0.13moles of sodium acetate in 1.0L after adding
0.02 moles of KOH?
c. What will the pH be if 0.15mol HA (pKa= 2.00) and 0.27 mole
A- are mixed together...

PART A
How many grams of solid sodium
cyanide should be added to 0.500
L of a 0.135 M hydrocyanic acid
solution to prepare a buffer with a pH of 8.597
?
grams sodium cyanide = _________
g.
PART B
How many grams of solid potassium
fluoride should be added to 0.500
L of a 8.48×10-2M hydrofluoric
acid solution to prepare a buffer with a pH
of3.807 ?
grams potassium fluoride =
________ g.
PART C
How many grams of...

How many grams of solid sodium fluoride should be added to 0.500
L of a 0.248 M hydrofluoric acid solution to prepare a buffer with
a pH of 3.988 ? grams sodium fluoride = g.

How many grams of solid sodium fluoride should be added to 0.500
L of a 0.241 M hydrofluoric acid solution to prepare a buffer with
a pH of 3.720 ?

How many grams of solid potassium cyanide should be added to
1.00 L of a 0.239 M hydrocyanic acid solution to prepare a buffer
with a pH of 10.174 ?
grams potassium cyanide=

Part A: How many grams of solid ammonium
chloride should be added to 1.50
L of a 5.46×10-2 M
ammonia solution to prepare a buffer with a pH of
8.630?
Part B: How many grams of solid potassium
nitrite should be added to 2.00 L
of a 0.255 M nitrous acid
solution to prepare a buffer with a pH of
2.353?

How many grams of sodium fluoride (NaF) would need to be added
to 1.00 L of 0.19 M HF to yield a solution with pH = 4.93? (pKa of
HF = 3.17)

1.A lactic acid/lactate ion buffer solution contains 0.43 M
HC3H5O3 and 0.62 M C3H5O3−, respectively. The Ka value of lactic
acid is 1.4×10−4. Calculate the pH of this buffer.
2. Enter the formula of the conjugate base for the acid
H2PO4−.
Enter the formula of the conjugate base for the acid
CH3−NH3+.
Enter the formula of the conjugate base for the acid HSO4−.
Enter the formula of the conjugate base for the acid HNO2.
Enter the formula of the conjugate...

How many grams of sodium acetate
(NaC2H3O2) must be added to 2.0 L
of a 0.500M acetic acid solution to produce a buffer of
pH=5.00?
At what pH would this buffer have the highest capacity?

How many grams of dipotassium phthalate (242.3 g/mol) must be
added to 200 mL of 0.150 M potassium hydrogen phthalate to give a
buffer of pH 5.40? The Ka's for phthalic acid are 1.12 x 10-3 and
3.90 x 10-6.

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