Answer:
The answer is C I think..
Answer:
Equilibrium constant of the given reaction is 
Explanation:
....
....
The given reaction can be written as summation of the following reaction-


......................................................................................

Equilibrium constant of this reaction is given as-
![\frac{[NOBr]^{2}}{[N_{2}][O_{2}][Br_{2}]}](https://tex.z-dn.net/?f=%5Cfrac%7B%5BNOBr%5D%5E%7B2%7D%7D%7B%5BN_%7B2%7D%5D%5BO_%7B2%7D%5D%5BBr_%7B2%7D%5D%7D)
![=(\frac{[NOBr]}{[NO][Br_{2}]^{\frac{1}{2}}})^{2}(\frac{[NO]^{2}}{[N_{2}][O_{2}]})](https://tex.z-dn.net/?f=%3D%28%5Cfrac%7B%5BNOBr%5D%7D%7B%5BNO%5D%5BBr_%7B2%7D%5D%5E%7B%5Cfrac%7B1%7D%7B2%7D%7D%7D%29%5E%7B2%7D%28%5Cfrac%7B%5BNO%5D%5E%7B2%7D%7D%7B%5BN_%7B2%7D%5D%5BO_%7B2%7D%5D%7D%29)


Answer: 4.5 moles of
can be made from complete reaction of 3.0 moles of Al.
Explanation:
The given reaction equation is as follows.

This shows that 2 moles of Al reacts with 6 moles of HCl. So, the amount of HCl required to react with 1 mole Al is three times the amount of HCl.
Therefore, 3 moles of Al will react with 9 moles of HCl to give 3 moles of
and
moles of
.
The reaction equation now will be as follows.

The moles
can also be written as 4.5 moles.
Thus, we can conclude that 4.5 moles of
can be made from complete reaction of 3.0 moles of Al.
Answer: Option (C) is the correct answer.
Explanation:
When chemical composition of a substance is not changing in a chemical reaction then it is known as a physical change.
For example, when water change state, from ice to steam then it means solid state is changing into gaseous state.
Therefore, it is a physical change.
And, a reaction which causes change in chemical composition is known as a chemical change.
For example, 
Thus, we can conclude that we can see water change state, from ice to steam. This is a physical change in matter.
I think the answer the students average is 15 km?