26 elements are man-made ..........
Answer:
The correct option is a.
Explanation:

125 kPa
125kpa - 2x 4x x
Total pressure after reaction = 176 kPa
125 kPa - 2x + 4x + x = 176 kPa
x = 17
125 kpa - 2x = 125 kPa - 2(17) = 91 kPa
Initial pressure of the dinitrogen pentoxide ,(at t=0) =
Final pressure of the dinitrogen pentoxide, (at t = t) = P = 91 kPa
The rate constant is = 



It will take 113 minutes for the total pressure to reach 176 kPa.
Answer:
When hydrogen is passed over hot ferric oxide (FeO) hydrogen reacts with oxygen present in the compound and forms water (H2O) and pure Iron
Explanation: