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tekilochka [14]
3 years ago
8

Tyrosine absorbs maximally at 290 nm. A 0.2162 g sample containing some amount of Tyrosine was placed into a 250.0 mL volumetric

flask and diluted to the mark. This solution had an absorbance of 0.118 (at 290 nm) in a 2.00 cm pathlength cell. A sample of pure Tyrosine (MW - 1818 g/mole) weighing 12.4 mg was dissolved in a 100.0 mL of solution. A 10.0 mL aliquot of this 100.0 mL solution was added to a 250.0 mL flask and diluted to the mark. This last diluted sample had an absorbance of 0.473 at 290 nm in a 1.00 cm cell. Calculate the weight percent of Tyrosine in the sample. Assume no other compounds in the sample, except Tyrosine, absorb at 290 nm.A. 0.14 %
B. 0.069 %
C. 0.028 %
D. 0.040 %
E. 1.80 %
F. 2.63 %

Chemistry
1 answer:
mojhsa [17]3 years ago
7 0

Answer:

B. 0.069 %

Explanation:

It should be initially noted in this answer in particular that, the amino acids tryptophan and tyrosine have a very precise 280 nm absorption rate, which allows a direct A280 size of protein concentration. The 280 nm UV absorbance rate is regularly utilized to approximate protein concentration in laboratories due to its simplistic nature, its affordability and also the ease of usage.

kindly check the attached image below for the solution to the above question.

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The energy required to ionize a mole of potassium ions is 419 kJ/mol . What is the longest wavelength of light capable of this i
liraira [26]
<span>First divide the ionization energy by Avogadro's number to get the energy per atom of potassium;
</span>419 kj/mol / 6.023 x 10²³
= 4.19 x 10⁵ / 6.023 x 10²³ = 6.96 x 10⁻¹⁹
E = hc/λ
where lambda (λ<span>) is the wavelength, h is Planck's constant, c is the speed of light 
</span>E = 6.96 x 10⁻¹⁹ j/atom<span>
h =</span>6.63x10⁻³⁴<span> Js
c = 3 x 10</span>⁸ m/s
λ = ?
λ = hc/E = (6.63x10⁻³⁴ x 3 x 10⁸ ) / 6.96 x 10⁻¹⁹ = 285.8nm = 286nm
<span>The longest wavelength of light capable of this ionization is 286nm.</span>
3 0
3 years ago
Copper is plated on zinc by immersing a piece of zinc into a solution containing copper(II) ions. In the plating reaction, coppe
Aloiza [94]

Hey there!:

Copper plating on Zinc will occur via this simple reaction:

Cu²⁺   +   2 e⁻   ⇌   Cu

When a species gains electron, it is reduced. Its oxidation state is decreased. For example, in the above reaction Cu2+ gained 2 electron to get reduced to Cu. Its oxidation state changed from +2 to 0. Hence it is a reduction reaction.

So, the correct answer is  :

The copper II ions  gain two electrons and are reduced.

Answer B

Hope this helps!

8 0
3 years ago
The outline of a partial periodic table is shown.
vova2212 [387]

Answer:

I think section #3

Explanation:

When i was in science class in my memory it was always in that area

4 0
3 years ago
Read 2 more answers
Look at this compound, why does magnesium has dative and covalent bonds with nitrogen? ...?
HACTEHA [7]
<span>The solid lines between N and Mg are actually ionic bonds. N has 5 valence electrons (2 of which are paired). Of the 3 that are unpaired, 2 are part of covalent bonds with adjacent carbon atoms. N accepts an extra electron to complete its octet, but gets a formal charge of -1. This allows for formation of an ionic bond with Mg, which is +2. Two of these charged N atoms therefore neutralize the charge of the central Mg. As for the coordinate (dative) covalent bonds, Mg has empty orbitals - the ionic bonds with the charged N atoms give it only 4/8 possible valence electrons.


The other two N atoms (dotted lines) have a formal charge of 0 since they form three covalent bonds with adjacent carbon atoms, but they still have a lone pair. Therefore, just to improve stability, each of these N atoms can "donate" its lone pair to Mg in order to complete its octet.


I hope my answer has come to your help. Thank you for posting your question here in Brainly. We hope to answer more of your questions and inquiries soon. Have a nice day ahead!



</span>
4 0
3 years ago
If a certain gas occupies a volume of 10. L when the applied pressure is 5.0 atm , find the pressure when the gas occupies a vol
lorasvet [3.4K]

Answer:

20L is the new volume

Explanation:

In this case, moles and T° from the gas remain constant. This is the formula we must apply, to solve this:

P₁ . V₁ = P₂ . V₂

5 atm . 10 L = P₂ . 2.5L

P₂ = (5 atm . 10 L) / 2.5L →20L

5 0
3 years ago
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