1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Otrada [13]
3 years ago
15

Your task is to create a buffered solution. You are provided with 0.10 M solutions of formic acid and sodium formate. Formic aci

d has a pKa of 3.75. 2. Create approximately 20 mL of buffer solution with a pH of 4.25.
Chemistry
1 answer:
Anton [14]3 years ago
4 0

Answer:

15.2mL of the 0.10M sodium formate solution and 4.8mL of the 0.10M formic acid solution.

Explanation:

To find the pH of a buffer based on the concentration of the acid and conjugate base we must use Henderson-Hasselbalch equation:

pH = pKa + log [A⁻] / [HA]

<em>Where [A⁻] could be taken as moles of the sodium formate and [HA] moles of the formic acid</em>

<em />

4.25 = 3.75 + log [A⁻] / [HA]

0.5 = log [A⁻] / [HA]

3.162 = [A⁻] / [HA] <em>(1)</em>

<em></em>

As both solutions are 0.10M and you want to create 20mL of the buffer, the moles are:

0.10M  * 20x10⁻³L =

2x10⁻³moles = [A⁻] + [HA] <em>(2)</em>

Replacing (2) in (1):

3.162 = 2x10⁻³moles - [HA] / [HA]

3.162 [HA] = 2x10⁻³moles - [HA]

4.162[HA] = 2x10⁻³moles

[HA] = 4.805x10⁻⁴ moles

[A⁻] = 2x10⁻³moles - 4.805x10⁻⁴ moles = 1.5195x10⁻³moles

That means, to create the buffer you must add:

[A⁻] = 1.5195x10⁻³moles * (1L / 0.10mol) = 0.0152L =

<h3>15.2mL of the 0.10M sodium formate solution</h3>

[HA] = 4.805x10⁻⁴ moles * (1L / 0.10mol) = 0.0048L =

<h3>4.8mL of the 0.10M formic acid solution</h3>
You might be interested in
PLEASE HELP
torisob [31]

Decrease

Increase  

Increase

Decrease

Increase

Decrease

Hope this helps! :)

4 0
3 years ago
A generic weak acid with formula HA has a Ka = 2.76 x 10-8. Calculate the Kb for the conjugate base of the acid.
Reika [66]

Answer:

3.62x10⁻⁷ = Kb

Explanation:

The acid equilibrium of a weak acid, HX, is:

HX + H₂O ⇄ X⁻ + H₃O⁺

Where Ka = [X⁻] [H₃O⁺] / [HX]

And basic equilibrium of the conjugate base, is:

X⁻ + H₂O ⇄ OH⁻ + HX

Where Kb = [OH⁻] [HX] / [X⁻]

To convert Ka to Kb we must use water equilibrium:

2H₂O ⇄ H₃O⁺ + OH⁻

Where Kw = 1x10⁻¹⁴ = [OH⁻] [H₃O⁺]

Thus, we can obtain:

Kw = Ka*Kb

Solving for Kb:

Kw / Ka = Kb

1x10⁻¹⁴ /  2.76x10⁻⁸ =

3.62x10⁻⁷ = Kb

4 0
3 years ago
Calcium is an element. What is the smallest particle of calcium that has the same chemical properties of calcium?
Verdich [7]

Answer:

A. An Atom

Explanation:

An atom is the smallest particle of an element, having the same chemical properties as the bulk element.

5 0
2 years ago
Read 2 more answers
How did changing from a light drizzle to a downpour affect the river and the sediment un it
soldi70 [24.7K]

Answer:

The velocity of the river increased.

There was more erosion in the stream.

The type of sediment that moved changed.

Explanation:

6 0
3 years ago
Can someone provide a answer with explanation for this question? Thanks!
zhuklara [117]

Answer:

Explanation:

B

4 0
1 year ago
Other questions:
  • Which of the following is a solution? <br> Steel <br> Milk <br> Plastic <br> Water
    9·1 answer
  • Consider the substitution reaction that rakes place when (R)-3-bromo 3-methylhexane is treated with methanol. Which of the follo
    5·1 answer
  • If 28.0 grams of Pb(NO3)2 react with 18.0 grams of NaI, what mass of PbI2 can be produced? Pb(NO3)2 + NaI → PbI2 + NaNO3
    15·1 answer
  • Under certain conditions the solid and liquid states of water can exist in equilibrium how are these conditions indicated on the
    10·2 answers
  • 4. How many atoms of copper are in 4,5 moles of copper (II) chloride?
    11·1 answer
  • Balance the reaction. A coefficient of "1" is understood. Choose option "blank" for the correct answer if the coefficient is "1.
    8·1 answer
  • It supports respiration.​
    10·2 answers
  • Choose the statement that best describes the effect of temperature on atoms and molecules.
    15·2 answers
  • What is the density of an object with a mass of 53.7 g and a volume of 27.19 ml?
    11·1 answer
  • 6. A hot potato is sitting out on the counter. After 3 hours, you pick up the 5 points
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!