Chemistry, 21.11.2019 00:31 12375819

If 15 grams of an organic solid is dissolved in 80 ml of water, how many grams remain in the water after extraction with 50 ml of a solvent which has a partition (distribution) coefficient with water of 8? show calculations.

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Answer from: cnolasco3675

2.5 g

Explanation:

The partial coefficient (K) is the ratio of the solubility (S) of a solute in two different solvents. For the given problem:

K = Ssolvent/Swater

The solubility is the mass divided by the volume. If the fraction of the solute in water is called q, the fraction of it in the solvent is 1-q. Let's call m the initial mass of the solute, so, after the extraction:

mass at the solvent = (1-q)m

mass at water = qm

Ssolvent = (1-q)m/50

Swater = qm/80

8 = [(1-q)m/50]/qm/80

8 = 80*(1-q)/50q

400q = 80 - 80q

480q = 80

q = 0.167

The mass that remains at the water is:

0.167*15 = 2.5 g

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

Answer(28.02g/mol);

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If 15 grams of an organic solid is dissolved in 80 ml of water, how many grams remain in the water a...

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