What Can you be more clear --Molecules change it from being less dense
Complete Question
A student is extracting caffeine from water with dichloromethane. The K value is 4.6. If the student starts with a total of 40 mg of caffeine in 2 mL of water and extracts once with 6 mL of dichloromethane
The experiment above is repeated, but instead of extracting once with 6 mL the extraction is done three times with 2 mL of dichloromethane each time. How much caffeine will be in each dichloromethane extract?
Answer:
The mass of caffeine extracted is ![P = 39.8 \ mg](https://tex.z-dn.net/?f=P%20%3D%20%2039.8%20%5C%20mg)
Explanation:
From the question above we are told that
The K value is ![K = 4.6](https://tex.z-dn.net/?f=K%20%3D%20%204.6)
The mass of the caffeine is ![m = 40 mg](https://tex.z-dn.net/?f=m%20%20%3D%2040%20mg)
The volume of water is ![V = 2 mL](https://tex.z-dn.net/?f=V%20%20%3D%202%20mL)
The volume of caffeine is ![v_c = 2 mL](https://tex.z-dn.net/?f=v_c%20%3D%20%202%20mL)
The number of times the extraction was done is n = 3
Generally the mass of caffeine that will be extracted is
![P = m * [\frac{V}{K * v_c + V} ]^3](https://tex.z-dn.net/?f=P%20%3D%20%20m%20%20%2A%20%20%5B%5Cfrac%7BV%7D%7BK%20%2A%20%20v_c%20%2B%20V%7D%20%5D%5E3)
substituting values
![P = 40 * [\frac{2}{4.6 * 2 + 2} ]^3](https://tex.z-dn.net/?f=P%20%3D%20%2040%20%20%20%2A%20%20%5B%5Cfrac%7B2%7D%7B4.6%20%2A%20%202%20%2B%202%7D%20%5D%5E3)
![P = 39.8 \ mg](https://tex.z-dn.net/?f=P%20%3D%20%2039.8%20%5C%20mg)
Answer:
![Cd(s)|Cd^{2+}(aq) || Cu^{2+}(aq)|Cu(s)](https://tex.z-dn.net/?f=Cd%28s%29%7CCd%5E%7B2%2B%7D%28aq%29%20%7C%7C%20Cu%5E%7B2%2B%7D%28aq%29%7CCu%28s%29)
Explanation:
A galvanic cell is composed of two electrodes immersed in a suitable electrolyte and connected via a salt bridge. One of the electrodes serves as a cathode where reduction or gain of electrons takes place. The other half cell functions as an anode where oxidation or loss of electrons occurs.
The representation is given by writing the anode on left hand side followed by its ion with its molar concentration. It is followed by a salt bridge. Then the cathodic ion with its molar concentration is written and then the cathode.
As it is given that cadmium acts as anode, it must be on the left hand side and copper must be on right hand side.
![Cd(s)|Cd^{2+}(aq) || Cu^{2+}(aq)|Cu(s)](https://tex.z-dn.net/?f=Cd%28s%29%7CCd%5E%7B2%2B%7D%28aq%29%20%7C%7C%20Cu%5E%7B2%2B%7D%28aq%29%7CCu%28s%29)
Answer: 21 lawns per week
Explanation:
The average weekly rate refers to how many lawns were mowed per week given that 233 were done in 11 weeks.
Rate will be given by;
= Lawns mowed / Weeks taken
= 233 / 11
= 21 lawns per week
b,f,h are already balanced