Chemistry, 25.02.2020 04:01 Alayna1037

There is a substance in a solution (0.03 mole/liter). The length of cuvette is 2 cm and only 10% of the certain light beam is transmitted. What is the extinction coefficient of the substance

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Answer from: starboy1051

The molar absorptivity coefficient is, $16.67 M^{-1}cm^{-1}$ .

Explanation:

Using Beer-Lambert's law :

Formula used :

$A=\epsilon \times C\times l$

$A=\log \frac{I_o}{I}$

$\log \frac{I_o}{I}=\epsilon \times C\times l$

where,

A = absorbance of solution

C = concentration of solution = 0.03 mol/L=0.03 M

l = path length = 2 cm

I_o = incident light

= transmitted light

$\epsilon$ = molar absorptivity coefficient = ?

A compound absorb 90 % of the light and transmit 10% of light.

Transmittance = 10% = 0.1

$0.1=\frac{I}{I_o}$

$A=\log \frac{I_o}{I}=\log \frac{1}{0.1}=1$

Now put all the given values in the above formula, we get the molar absorptivity coefficient.

$1=\epsilon \times (0.03 M)\times ( 2 cm)$

$\epsilon=16.67 M^{-1}cm^{-1}$

Therefore, the molar absorptivity coefficient is, $16.67 M^{-1}cm^{-1}$ .

Answer from: Quest

assuming that your periodic table has eighteen columns, you should highlight the four elements in the third column from the left of the table.

explanation

neutral atoms of elements after calcium contain d electrons. the energy of d orbitals of a particular main shell lies between the energy of the s and p orbitals of the next main shell. for example, electrons in the $3d$ have energy higher than those in the $4 s$ orbital while lower than those of the $4 p$ orbital.

by the aufbau principle, electrons fill orbitals one at a time, starting from those of the lowest energy. the $4s$ orbital is therefore filled right after $3p$ orbitals and before $3 d$ orbitals.

potassium has electron configuration $[\text{ar}] 4 s^{1}$ and calcium $[\text{ar}] 4 s^{2}$ . the s orbital of a main shell holds a maximum of two electrons. the next element would thus have the electron configuration $[\text{ar}] 4 s^{2} \; 3d^{1}$ and satisfy the requirements.

a neutral atom of the element contains three electrons on top of the most recent noble gas element. it should thus be placed in the third column of the periodic table. both scandium and yttrium would satisfy the conditions. an aufbau diagram indicates that the 4f orbital is filled before the 5d. however, it appears that exceptions exists for both lanthanum and actinium. neutral atoms of the two d-block elements also demonstrate the $ns^{2} \; (n-1) p^{1}$ and should be highlighted as well.

Answer from: Quest

The answer is 323 g.

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There is a substance in a solution (0.03 mole/liter). The length of cuvette is 2 cm and only 10% of...

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