Answer: The equilibrium constant for the given reaction is 0.0421.
Explanation:

Concentration of
= 0.0095 M
Concentration of
= 0.020 M
Concentration of
= 0.020 M
The expression of the equilibrium constant is given as:
![K_c=\frac{[PCl_3][Cl_2]}{[PCl_5]}=\frac{0.020 M\times 0.020 M}{0.0095 M}](https://tex.z-dn.net/?f=K_c%3D%5Cfrac%7B%5BPCl_3%5D%5BCl_2%5D%7D%7B%5BPCl_5%5D%7D%3D%5Cfrac%7B0.020%20M%5Ctimes%200.020%20M%7D%7B0.0095%20M%7D)
(An equilibrium constant is an unit less constant)
The equilibrium constant for the given reaction is 0.0421.
Valence.
The electrons in the outer shell of an atom are called valence electrons.
Valence electrons determine whether the an element is ready form compounds. These electrons can be gained, lost, or shared in the formation of compounds.
Effect of increasing surface area on the rate of a reaction. ... Increasing the surface area of a solid reactant exposes more of its particles to attack. This results in an increased chance of collisions between reactant particles, so there are more collisions in any given time and the rate of reaction increases.
There are two hydrogen and two oxygen molecules because the number next to the atomic number is how many there are.