Answer:
4.94g of material
Explanation:
Partition coefficient (Kp) of a substance is defined as the ratio between concentration of organic solution and aqueous solution, that is:
Kp = <em>8 = Concentration in Ethyl acetate / Concentration in water</em>
100mL of a 5% solution contains 5g of material in 100mL of water. Thus:
8 = X / 100mL / (5g-X) / 100mL
<em>Where X is the amount of material in grams that comes to the organic phase.</em>
8 = X / 100mL / (5g-X) / 100mL
8 = 100X / (500-100X)
4000 - 800X = 100X
4000 = 900X
4.44g = X
<em>Thus, in the first extraction you will lost 4.44g of material from the aqueous phase.</em>
And will remain 5g-4.44g = 0.56g.
In the second extraction:
8 = X / 100mL / (0.56g-X) / 100mL
8 = 100X / (56-100X)
448 - 800X = 100X
448 = 900X
0.50g = X
<em>In the second extraction, you will extract 0.50g of material</em>
Thus, after the two extraction you will lost:
4.44g + 0.50g = <em>4.94g of material</em>
<em></em>
Answer:
a): not necessarily due to London Dispersion Forces and dipole-dipole interactions.
b): not necessarily due to London Dispersion Forces.
Explanation:
There are three major types of intermolecular interaction:
- Hydrogen bonding between molecules with H-O, H-N, or H-F bonds and molecules with lone pairs.
- Dipole-dipole interactions between all molecules.
- London dispersion forces between all molecules.
The melting point of a substance is a result of all three forces, combined.
Note that the more electrons in each molecule, the stronger the London Dispersion Force. Generally, that means the more atoms in each molecule, the stronger the London dispersion force. The strength of London dispersion force between large molecules can be surprisingly strong.
For example, 
(water) molecules are capable of hydrogen bonding. The melting point of at 
is around 
. That's considerably high when compared to other three-atom molecules.
In comparison, the higher alkane hexadecane (
, straight-chain) isn't capable of hydrogen bonding. However, under a similar pressure, hexadecane melts at around 
above the melting point of water. The reason is that with such a large number of atoms (and hence electrons) per molecule, the London dispersion force between hexadecane molecules could well be stronger than that the hydrogen bonding between water molecules.
Similarly, the dipole moments in HCl (due to the highly-polar H-Cl bonds) are much stronger than those in hexadecane (due to the C-H bonds.) However, the boiling point of hexadecane under standard conditions is much higher (at around 
than that of HCl.
