Answer:
Some of the physical changes used by the industrial chemist in order to identify it is by scratching it with other metals in order to find the hardness of it. Trying to deform it in order to find the malleability, and to heat it and measure the temperature in order to find the melting point.
Some of the chemical changes used by the industrial chemist in order to identify it is by inserting it in water to observe that whether it reacts with it or not, if the reaction is violent, then the metal belongs to either group I or group II. The other method is to insert it in acids of distinct strength and to observe its reaction. The metals belonging to the second group react briskly with acids. The other metals react gradually with acids and others are almost inert.
Solid should be the anwser
Burrows, tracks, coprolites, nests and footprints are examples of traces that can be found in a fossil.
<u>Answer:</u> The value of equilibrium constant is 0.997
<u>Explanation:</u>
We are given:
Percent degree of dissociation = 39 %
Degree of dissociation, 
= 0.39
Concentration of 
, c = 
The given chemical equation follows:
<u>Initial:</u> c -
<u>At Eqllm:</u> 
So, equilibrium concentration of ![N_2O_4=c-c\alpha =[1-(1\times 0.39)]=0.61M](https://tex.z-dn.net/?f=N_2O_4%3Dc-c%5Calpha%20%3D%5B1-%281%5Ctimes%200.39%29%5D%3D0.61M)
Equilibrium concentration of ![NO_2=2c\alpha =[2\times 1\times 0.39]=0.78M](https://tex.z-dn.net/?f=NO_2%3D2c%5Calpha%20%3D%5B2%5Ctimes%201%5Ctimes%200.39%5D%3D0.78M)
The expression of 
for above equation follows:
![K_{c}=\frac{[NO_2]^2}{[N_2O_4]}](https://tex.z-dn.net/?f=K_%7Bc%7D%3D%5Cfrac%7B%5BNO_2%5D%5E2%7D%7B%5BN_2O_4%5D%7D)
Putting values in above equation, we get:
Hence, the value of equilibrium constant is 0.997
