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 
Explanation:
From the question above we are told that
The K value is 
The mass of the caffeine is 
The volume of water is 
The volume of caffeine is 
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)
A chemical formula identifies each constituent element by its chemical symbol and indicates the proportionate number of atoms of each element.
<em>For example, the empirical formula of ethanol may be written C2H6O because the molecules of ethanol all contain two carbon atoms, six hydrogen atoms, and one oxygen atom.</em>
<u>Answer:</u> The equilibrium concentration of HCl is 
<u>Explanation:</u>
We are given:
Moles of 
= 0.564 moles
Volume of vessel = 1.00 L
Molarity is calculated by using the equation:
Molarity of 
The given chemical equation follows:
<u>Initial:</u> 0.564
<u>At eqllm:</u> 0.564-x x x
The expression of 
for above equation follows:
![K_c=[NH_3][HCl]](https://tex.z-dn.net/?f=K_c%3D%5BNH_3%5D%5BHCl%5D)
The concentration of pure solid and pure liquid is taken as 1.
We are given:
Putting values in above equation, we get:
Negative sign is neglected because concentration cannot be negative.
So, ![[HCl]=2.26\times 10^{-3}M](https://tex.z-dn.net/?f=%5BHCl%5D%3D2.26%5Ctimes%2010%5E%7B-3%7DM)
Hence, the equilibrium concentration of HCl is
Answer:
The metal cube lattice is made of only one kind of atom.
Explanation:
As we know that metallic crystals are made up of only one kind of element. A metal crystal is actually a huge sea of positive charges embedded in the layers of negative charges (electrons). The whole crystal is made up of same kind of atoms, e.g crystals of gold, crystals of iron.
If we talk about structure of metallic crystal, it can be body centered cubic, simple cubic, hexagonal or close cubic packing.
Now, coming towards the ionic crystals, we know that they are basically the crystals of ionic compounds like sodium chloride or cesium chloride. These crystals are formed due to ionic bonding between two or more than two kinds of elements/atoms. It is not possible for an ionic crystal to be composed of only one kind of atom. As far as structure is concerned, they can have different structure based on bonding between atoms in an ionic compound, e.g NaCl has octahedral geometry.
Therefore, it is very evident that best option is A.
