Actual question from source:-
A 3.96x10-4 M solution of compound A exhibited an absorbance of 0.624 at 238 nm in a 1.000 cm cuvette. A blank had an absorbance of 0.029. The absorbance of an unknown solution of compound A was 0.375. Find the concentration of A in the unknown.
Answer:
Molar absorptivity of compound A = 
Explanation:
According to the Lambert's Beer law:-
Where, A is the absorbance
l is the path length
is the molar absorptivity
c is the concentration.
Given that:-
c = 
Path length = 1.000 cm
Absorbance observed = 0.624
Absorbance blank = 0.029
A = 0.624 - 0.029 = 0.595
So, applying the values in the Lambert Beer's law as shown below:-

<u>Molar absorptivity of compound A =
</u>
The equilibrium constant of a reaction is defined as:
"The ratio between equilibrium concentrations of products powered to their reaction quotient and equilibrium concentration of reactants powered to thier reaction quotient".
The reaction quotient, Q, has the same algebraic expressions but use the actual concentrations of reactants.
To solve this question we need this additional information:
<em>For this reaction, K = 6.0x10⁻² and the initial concentrations of the reactants are:</em>
<em>[N₂] = 4.0M; [NH₃] = 1.0x10⁻⁴M and [H₂] = 1.0x10⁻²M</em>
<em />
Thus, for the reaction:
N₂ + 3H₂ ⇄ 2NH₃
The equilibrium constant, K, of this reaction, is defined as:
![K = 6.0x10^{-2} = \frac{[NH_3]^2}{[N_2][H_2]^3}](https://tex.z-dn.net/?f=K%20%3D%206.0x10%5E%7B-2%7D%20%3D%20%5Cfrac%7B%5BNH_3%5D%5E2%7D%7B%5BN_2%5D%5BH_2%5D%5E3%7D)
And Q, is:
![Q = \frac{[NH_3]^2}{[N_2][H_2]^3}](https://tex.z-dn.net/?f=Q%20%3D%20%5Cfrac%7B%5BNH_3%5D%5E2%7D%7B%5BN_2%5D%5BH_2%5D%5E3%7D)
Where actual concentrations are:
[NH₃] = 1.0x10⁻⁴M
[N₂] = 4.0M
[H₂] = 2.5x10⁻¹M
Replacing:
![Q = \frac{[1.0x10^{-4}]^2}{[4.0][2.5x10^{-1}]^3}](https://tex.z-dn.net/?f=Q%20%3D%20%5Cfrac%7B%5B1.0x10%5E%7B-4%7D%5D%5E2%7D%7B%5B4.0%5D%5B2.5x10%5E%7B-1%7D%5D%5E3%7D)
<h3>Q = 1.6x10⁻⁷</h3>
As Q < K,
<h3>The chemical system will shift to the right in order to produce more NH₃</h3>
Learn more about chemical equililbrium in:
brainly.com/question/24301138
Explanation:
It is known that efficiency is denoted by
.
The given data is as follows.
= 0.82,
= (21 + 273) K = 294 K
= 200 kPa,
= 1000 kPa
Therefore, calculate the final temperature as follows.
0.82 =
= 1633 K
Final temperature in degree celsius =
= 
Now, we will calculate the entropy as follows.

For 1 mole, 
It is known that for
the value of
= 0.028 kJ/mol.
Therefore, putting the given values into the above formula as follows.

= 
= 0.0346 kJ/mol
or, = 34.6 J/mol (as 1 kJ = 1000 J)
Therefore, entropy change of ammonia is 34.6 J/mol.
Answer:
11482 ppt of Li
Explanation:
The lithium is extracted by precipitation with B(C₆H₄)₄. That means moles of Lithium = Moles B(C₆H₄)₄. Now, 1 mole of B(C₆H₄)₄ produce the liberation of 4 moles of EDTA. The reaction of EDTA with Mg²⁺ is 1:1. Thus, mass of lithium ion is:
<em>Moles Mg²⁺:</em>
0.02964L * (0.05581mol / L) = 0.00165 moles Mg²⁺ = moles EDTA
<em>Moles B(C₆H₄)₄ = Moles Lithium:</em>
0.00165 moles EDTA * (1mol B(C₆H₄)₄ / 4mol EDTA) = 4.1355x10⁻⁴ mol B(C₆H₄)₄ = Moles Lithium
That means mass of lithium is (Molar mass Li=6.941g/mol):
4.1355x10⁻⁴ moles Lithium * (6.941g/mol) = 0.00287g. In μg:
0.00287g * (1000000μg / g) = 2870μg of Li
As ppt is μg of solute / Liter of solution, ppt of the solution is:
2870μg of Li / 0.250L =
<h3>11482 ppt of Li</h3>
Answer:
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