<u>Answer:</u> The time required will be 19.18 years
<u>Explanation:</u>
All the radioactive reactions follows first order kinetics.
The equation used to calculate half life for first order kinetics:

We are given:

Putting values in above equation, we get:

Rate law expression for first order kinetics is given by the equation:
![k=\frac{2.303}{t}\log\frac{[A_o]}{[A]}](https://tex.z-dn.net/?f=k%3D%5Cfrac%7B2.303%7D%7Bt%7D%5Clog%5Cfrac%7B%5BA_o%5D%7D%7B%5BA%5D%7D)
where,
k = rate constant = 
t = time taken for decay process = ?
= initial amount of the reactant = 2 g
[A] = amount left after decay process = (2 - 0.5) = 1.5 g
Putting values in above equation, we get:

Hence, the time required will be 19.18 years
The answer is C) iron and oxygen. The reactants are on the left side of the equation
Answer:
The two conditions that can limit the usefulness of the kinetic-molecular theory in describing gas behavior are "high pressure" and "low temperatures". At low temperatures or high pressures, real gases deviate significantly from ideal gas behavior.
Explanation:
Answer:
C
Explanation:
Element Z acquires two electrons from element X for stability
Answer:
421,787 moles.
Explanation:
No. of Molecules of H20=2.54×10²⁹
1 mole=6.022×10²³=Avagadro No.
No. of moles=Given no. of moles/Avagadro No.
=(2.54×10²⁹)/(6.022×10²³)=421,786.782=421,787(approx)