Answer:
Elements are classified into- metals – Nonmetals- Metalloids – Noble gases. State which of A, B, C, D is a:
1) Metallic element
2) Non-metallic element
3) Metalloid
4) Noble gas.
A) Is non-malleable, non-ductile and a poor conductor of electricity
B) Has lustre, is malleable and ductile and a good conductor of electricity
C) Is unreactive and inert and present in traces in air
D) Shows properties of both metals and nonmetals
Explanation:
An electron should emit energy to return to its original energy level from a higher energy level.
<h3>What is an energy level?</h3>
Energy levels (also called electron shells) are fixed distances from the nucleus of an atom where electrons may be found.
The electron absorbs the energy and jumps to a higher energy level. In the reverse process, emission, the electron returns to the ground state by releasing the extra energy that is absorbed.
Hence, an electron should emit energy to return to its original energy level from a higher energy level.
Learn more about the energy level here:
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Answer : The molarity after a reaction time of 5.00 days is, 0.109 M
Explanation :
The integrated rate law equation for second order reaction follows:
![k=\frac{1}{t}\left (\frac{1}{[A]}-\frac{1}{[A]_o}\right)](https://tex.z-dn.net/?f=k%3D%5Cfrac%7B1%7D%7Bt%7D%5Cleft%20%28%5Cfrac%7B1%7D%7B%5BA%5D%7D-%5Cfrac%7B1%7D%7B%5BA%5D_o%7D%5Cright%29)
where,
k = rate constant = 
t = time taken = 5.00 days
[A] = concentration of substance after time 't' = ?
= Initial concentration = 0.110 M
Now put all the given values in above equation, we get:
![9.7\times 10^{-6}=\frac{1}{5.00}\left (\frac{1}{[A]}-\frac{1}{(0.110)}\right)](https://tex.z-dn.net/?f=9.7%5Ctimes%2010%5E%7B-6%7D%3D%5Cfrac%7B1%7D%7B5.00%7D%5Cleft%20%28%5Cfrac%7B1%7D%7B%5BA%5D%7D-%5Cfrac%7B1%7D%7B%280.110%29%7D%5Cright%29)
![[A]=0.109M](https://tex.z-dn.net/?f=%5BA%5D%3D0.109M)
Hence, the molarity after a reaction time of 5.00 days is, 0.109 M
Powdered coke prevent the heat loss. As a result, it prevents burning of carbon electrodes.