Explanation:
Compounds are the species in which all the components react chemically to form a molecule which has a different property from the constituting elements.
On the other hand, mixture are the species in which the components do not react chemically and the original properties of the components are not lost.
<u>Thus, separation of the mixture into its components can be done by the physical means while separation of the compound into its components can be only possible by the chemical means.</u>
Answer:
All of the above
Explanation:
I believe all three are true. They see how the organism is similar to other organisms. They see if the organism has the characteristics of an animal or plant. They look at what makes the organism unique.
Explanation:
Noble gas configuration is defined as the configuration which contains completely filled orbitals.
For example, oxygen atom when gain two electrons then it forms oxygen ion (
).
Atomic number of oxygen atom is 8 and so, its number of electrons will also be 8. But when it gain two electrons then it has total 10 electrons. Hence, electronic configuration of
is as follows.

Since, there are completely filled orbitals in an
ions. Therefore, it means this ion has a noble-gas configuration.
Thus, we can conclude that any specie which shows completely filled orbitals will have noble-gas configuration.
Answer : The value of acid dissociation constant is, 
Solution : Given,
Concentration pyridinecarboxylic acid = 0.78 M
pH = 2.53
First we have to calculate the hydrogen ion concentration.
![pH=-\log [H^+]](https://tex.z-dn.net/?f=pH%3D-%5Clog%20%5BH%5E%2B%5D)
![2.53=-\log [H^+]](https://tex.z-dn.net/?f=2.53%3D-%5Clog%20%5BH%5E%2B%5D)
![[H^+]=2.95\times 106{-3}M](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D2.95%5Ctimes%20106%7B-3%7DM)
Now we have to calculate the acid dissociation constant.
The equilibrium reaction for dissociation of (weak acid) is,

initially conc. 0.78 0 0
At eqm. (0.78-x) x x
The expression of acid dissociation constant for acid is:
![k_a=\frac{[C_6H_4NO_2^-][H^+]}{[C_6H_4NO_2]}](https://tex.z-dn.net/?f=k_a%3D%5Cfrac%7B%5BC_6H_4NO_2%5E-%5D%5BH%5E%2B%5D%7D%7B%5BC_6H_4NO_2%5D%7D)
As, ![[H^+]=[C_6H_4NO_2^-]=x](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D%5BC_6H_4NO_2%5E-%5D%3Dx)
So, 
Now put all the given values in this formula ,we get:



Therefore, the value of acid dissociation constant is, 