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
Fynjy0 [20]
3 years ago
11

What is the [ch3co2-]/[ch3co2h] ratio necessary to make a buffer solution with a ph of 4.34? ka = 1.8 × 10-5 for ch3co2h?

Chemistry
1 answer:
xeze [42]3 years ago
5 0
According to Henderson–Hasselbalch Equation,

                                    pH  =  pKa + log [Acetate] / [Acetic Acid]

As,
           pKa = -log Ka
           pKa = -log (1.8 × 10⁻⁵)
           pKa =  4.74
So,
                               pH  =  4.74 + log [Acetate] / [Acetic Acid]

                                  4.34  =  4.74 + log [Acetate] / [Acetic Acid]

                        4.34 - 4.74  = log [Acetate] / [Acetic Acid]

                                 -0.40  =  log [Acetate] / [Acetic Acid]

Taking Antilog on both sides,

               [Acetate] / [Acetic Acid]  =  0.398
You might be interested in
Which of these is indication that a chemical reaction has occurred?
trasher [3.6K]
B.melting of a substance
3 0
3 years ago
Read 2 more answers
Calculate the missing variables in each experiment below using Avogadro’s law.
blagie [28]

Answer:

The answer to your question is: letter c

Explanation:

Data

V1 = 612 ml    n1 = 9.11 mol

V2 = 123 ml    n2 = ?

Formula

                               \frac{V1}{n1}  =  \frac{V2}{n2}

                                         n2 = \frac{n1V2}{V1}

                                         n2 = \frac{(9.11)((123)}{(612)}

                                                n2 = 1.83 mol                                                

5 0
3 years ago
Questions are in the image B and 4i
Keith_Richards [23]
Dimitri mastered in Elements
7 0
2 years ago
A solution is prepare using 45.2 g of an unknown (nonelectrolyte) dissolved in 476.4 g of water. The freezing point depression
Ray Of Light [21]

Answer:

94.4g/mol is molar mass of the unknown

Explanation:

Based on the freezing point depression equation:

ΔT = Kf*m*i

<em>Where ΔT is the depression in freezing point (1.87°C)</em>

<em>Kf is freezing point depression constant of water (1.86°Ckg/mol)</em>

<em>And i is Van't Hoff factor (1 for nonelectrolyte solutes)</em>

<em />

Replacing:

1.87°C = 1.86°CKg/mol*m*i

1.005mol/kg solvent = m

Using the mass of the solvent we can find the oles of the nonelectrolyte:

1.005mol/kg solvent * 0.4764kg = 0.479moles

Molar mass is defined as the ratio between mass of a substance in grams and moles, that is:

45.2g / 0.479mol =

<h3>94.4g/mol is molar mass of the unknown</h3>
6 0
3 years ago
Determine the pH of the resulting solution if 25 mL of 0.400 M strychnine (C21H22N2O2) is added to 50 mL of 0.200 M HCl? Assume
DIA [1.3K]

Answer:

pH = 4.56

Explanation:

The strychnine reacts with HCl as follows:

C₂₁H₂₂N₂O₂ + HCl ⇄ C₂₁H₂₂N₂O₂H⁺ + Cl⁻

<em />

For strychnine buffer:

pOH = 5.74 + log [C₂₁H₂₂N₂O₂H⁺] / [C₂₁H₂₂N₂O₂]

Initial moles of C₂₁H₂₂N₂O₂ are:

0.025L * (0.400 mol / L) = 0.01 moles C₂₁H₂₂N₂O₂

And of HCl are:

0.05L * (0.200 mol / L) = 0.01 moles HCl

That means after the reaction, you will have just 0.01 moles of C₂₁H₂₂N₂O₂H⁺ in 50mL + 25mL = 0.075L. And molarity is:

[C₂₁H₂₂N₂O₂H⁺] = 0.01 mol / 0.075L = 0.1333M

This conjugate acid, is in equilibrium with water as follows:

C₂₁H₂₂N₂O₂H⁺(aq) + H₂O(l) ⇄ C₂₁H₂₂N₂O₂ + H₃O⁺

<em />

<em>Where Ka = Kw / Kb = 1x10⁻¹⁴ / 1.8x10⁻⁶ = 5.556x10⁻⁹</em>

<em />

Ka is defined as:

Ka = 5.556x10⁻⁹ = [C₂₁H₂₂N₂O₂] [H₃O⁺] / [C₂₁H₂₂N₂O₂H⁺]

In equilibrium, concentrations are:

C₂₁H₂₂N₂O₂ = X

H₃O⁺ = X

C₂₁H₂₂N₂O₂H⁺ = 0.1333M - X

Replacing in Ka expression:

5.556x10⁻⁹ = [X] [X] / [0.1333M - X]

7.39x10⁻¹⁰ - 5.556x10⁻⁹X = X²

7.39x10⁻¹⁰ - 5.556x10⁻⁹X - X² = 0

Solving for X:

X = - 2.72x10⁻⁵M → False solution. There is no negative concentrations

X = 2.72x10⁻⁵M → Right solution.

As H₃O⁺ = X

H₃O⁺ = 2.72x10⁻⁵M

And pH = -log H₃O⁺

<h3>pH = 4.56</h3>
4 0
3 years ago
Other questions:
  • Which is one way that scientist communicate the result of an experiment
    10·1 answer
  • Calculate the mass of 139 cm^3 Argon at STP
    6·1 answer
  • Balance the following redox equation, identifying the element oxidized and the element reduced. Show all of the work used to sol
    13·1 answer
  • Convert the following reaction into its formula equation and complete the product.
    5·1 answer
  • What test or tests do you use to find NaCl
    12·2 answers
  • An isotope of the element fluorine has 9 protons and 10 neutrons. What is the name of this isotope?fluorine
    5·2 answers
  • The symbol ∆hf0 stands for
    13·1 answer
  • What mass of radon is in 8.17 moles of radon?
    14·1 answer
  • if kept at a constant temperature, what is the concentration at 865s if the initial concentration was 0.0225M
    15·1 answer
  • PLEASE HELP ME WITH THID IFK IT!! ILL GIVE YOU EXTRA POINTS
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!