Answer:
Diffusion means that particles travel from a higher concentration to a lower concentration region before balance is achieved. The semi-permeable membrane is present in osmosis, so that only solvent molecules can travel freely to equalize the levels.
The answer is A. A mole of Cu has the same number of atoms as a mole of He atoms
Answer:
A liquid-fueled rocket has two liquids (liquids are good because of the density, they need less space than a gas to be stored), such that these liquids are called the fuel and the oxidizer.
These liquids are injected into a system that leads to a combustion chamber, where the liquids are mixed (we need to mix the fuel with the oxidizer to enable the combustion of the fuel) and burned to produce thrust.
Some common examples of oxidizers are liquid oxygen, which may be combined with fuels like liquid hydrogen, liquid methane, kerosene and hydrazine.
Other oxidizers are liquid fluorine (which also can be combined with the fuels liquid hydrogen and hydrazine), nitrogen tetroxide (which can be combined whit kerosene, hydrazine and other fuels) and FLOX-70, which can only be combined with kerosene.
The "most commonly used" may depend on the country and the type of liquid propellant ( petroleum, cryogens, and hypergols)
Such that the most common oxidizer may be liquid oxygen, and the most common fuel the kerosene.
The answer is <span>D.when the aim is to show electron distributions in shells. This is because there are some instances when elements don't possess a regular or normal electron configuration. There are those who have special electron configurations wherein a lower subshell isn't completely filled before occupying a higher subshell. It is best to visualize such cases using the orbital notation.</span>
The given question is incomplete. The complete question is as follows.
Sodium sulfate is slowly added to a solution containing 0.0500 M 
and 0.0390 M 
. What will be the concentration of 
(aq) when 
begins to precipitate? What percentage of the can be separated from the Ag(aq) by selective precipitation?
Explanation:
The given reaction is as follows.
![[Ag^{+}]](https://tex.z-dn.net/?f=%5BAg%5E%7B%2B%7D%5D)
= 0.0390 M
When 
precipitates then expression for 
will be as follows.
![K_{sp} = [Ag^{+}]^{2}[SO^{2-}_{4}]](https://tex.z-dn.net/?f=K_%7Bsp%7D%20%3D%20%5BAg%5E%7B%2B%7D%5D%5E%7B2%7D%5BSO%5E%7B2-%7D_%7B4%7D%5D)
![1.20 \times 10^{-5} = (0.0390)^{2} \times [SO^{2-}_{4}]](https://tex.z-dn.net/?f=1.20%20%5Ctimes%2010%5E%7B-5%7D%20%3D%20%280.0390%29%5E%7B2%7D%20%5Ctimes%20%5BSO%5E%7B2-%7D_%7B4%7D%5D)
![[SO^{2-}_{4}]](https://tex.z-dn.net/?f=%5BSO%5E%7B2-%7D_%7B4%7D%5D)
= 0.00788 M
Now, equation for dissociation of calcium sulfate is as follows.
![K_{sp} = [Ca^{2+}][SO^{2-}_{4}]](https://tex.z-dn.net/?f=K_%7Bsp%7D%20%3D%20%5BCa%5E%7B2%2B%7D%5D%5BSO%5E%7B2-%7D_%7B4%7D%5D)
![4.93 \times 10^{-5} = [Ca^{2+}] \times 0.00788](https://tex.z-dn.net/?f=4.93%20%5Ctimes%2010%5E%7B-5%7D%20%3D%20%5BCa%5E%7B2%2B%7D%5D%20%5Ctimes%200.00788)
![[Ca^{2+}]](https://tex.z-dn.net/?f=%5BCa%5E%7B2%2B%7D%5D)
= 0.00625 M
Now, we will calculate the percentage of remaining in the solution as follows.
= 12.5%
And, the percentage of that can be separated is as follows.
100 - 12.5
= 87.5%
Thus, we can conclude that 87.5% will be the concentration of when begins to precipitate.
