Answer:
B. 4 Fe + 3 0₂---> 2 Fe₂O3
Explanation:
(A) Ir + O₂--> IrO₂ No: Ir is iridium
(B) 4 Fe + 3 0₂---> 2 Fe₂O3 Yes: Fe is iron and O is oxygen, and the equation is balanced.
(C) I+ 0₂ ---> 10₂ No: I is iodine
(D) 3 Ir + 0₂ -> 6 Ir₂03 No: I is iodine
C. Also just look up a chemical equation balancer calculator next time.
First, assume the order of the given reaction is n, then the rate of reaction i.e. ![\frac{dx}{dt}=k\times[A]^{n}](https://tex.z-dn.net/?f=%5Cfrac%7Bdx%7D%7Bdt%7D%3Dk%5Ctimes%5BA%5D%5E%7Bn%7D)
where, dx is change in concentration of A in small time interval dt and k is rate constant.
According to units of rate constant, the reaction is of second order.
(second order formula)
Put the values,

t= 587.9 s
Hence, time taken is 587.9 s
If an unknown substance CANNOT be broken down into simpler substances, it is AN ELEMENT made of one kind of atom.
Ans: 50m per sec
Explanation:
Speed= distance / time
therefore speed = 100m/2sec
=50m per sec