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andrew11 [14]
3 years ago
9

A 1.0 m solution of a compound with 2 ionizable groups (pka's = 6.2 and 9.5; 100 ml total) has a ph of 6.8. what are the concent

rations of the relevant acid and conjugate base?
Chemistry
1 answer:
aleksklad [387]3 years ago
3 0

Answer:

[H₂A] = 0.2M

[HA⁻] = 0.8M

Explanation:

A compound with 2 ionizable groups has as equilbriums:

H₂A ⇄ HA⁻ + H⁺ ⇄ A²⁻ + H⁺

A pH of 6.8 is near to the first equilibrium:

H₂A ⇄ HA⁻ + H pKa = 6.2

To determine concentrations of the acid H₂A and conjugate base HA⁻ we use H-H equation:

pH = pKA + log [HA⁻] / [H₂A]

6.8 = 6.2 + log [HA⁻] / [H₂A]

0.6 = log [HA⁻] / [H₂A]

3.981 = [HA⁻] / [H₂A] <em>(1)</em>

As concentration of the buffer is 1.0M:

1M = [HA⁻] + [H₂A] <em>(2)</em>

Replacing (2) in (1):

3.981 = 1- [H₂A] / [H₂A]

3.981[H₂A] = 1 - [H₂A]

4.981 [H₂A] = 1

[H₂A] = 0.2M

And [HA] = 1M - 0.2M = 0.8M

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Answer:

= 913.84 mL

Explanation:

Using the combined gas laws

P1V1/T1 = P2V2/T2

At standard temperature and pressure. the pressure is 10 kPa, while the temperature is 273 K.

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T1 = -12.5 + 273 = 260.5 K

P2 = 10 kPa

V2 = ?

T2 = 273 K

Therefore;

V2 = P1V1T2/P2T1

     = (109 kPa × 80 mL × 273 K)/(10 kPa× 260.5 K)

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The new volume : 0.07 L

<h3>Further explanation</h3>

Boyle's Law  

At a constant temperature, the gas volume is inversely proportional to the pressure applied  

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P₁=1 atm

V₁=0.39 L

P₂=5.6 atm

\tt V_2=\dfrac{P_1.V_1}{P_2}\\\\V_2=\dfrac{1\times 0.39}{5.6}\\\\v_2=\boxed{\bold{0.07~L}}

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What atoms make up a carboxyl group?
statuscvo [17]

Answer:

The answer to your question is below

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Carboxyl group is the characteristic group of carboxylic acids.

It is composed by 1 atom of carbon, 2 atoms of oxygen and 1 atom of hydrogen.

Its structure is   - COOH

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A.

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Consider the reaction 2NO(g) 1 O2(g) ¡ 2NO2(g) Suppose that at a particular moment during the reaction nitric oxide (NO) is reac
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The rate in terms of reactants is given as negative as the concentration of reactants is decreasing with time whereas the rate in terms of products is given as positive as the concentration of products is increasing with time.

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2. The rate of disappearance of O_2

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Learn more about rate law

brainly.com/question/13019661

https://brainly.in/question/1297322

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