Answer:
Here, we are required to determine the total energy of the reaction and determine if the reaction is an endothermic or exothermic reaction.
The correct answer is option C.
First, we need to determine the energy of the reaction.
The energy of the reaction is the change in enthalpy between the product and reactants.
Change of Enthalpy,
Hreaction = Hproduct - Hreactant.
Therefore, for the reaction above, the change in enthalpy is:
Hreaction = 590kJ/mol - 581kJ/mol.
Hreaction = 9kJ/mol.
Hence, since the reaction has an enthalpy change of 9kJ/mol, the reaction is endothermic (i.e energy is absorbed).
Explanation:
The radioactive decay obeys first order kinetics
the rate law expression for radioactive decay is
![ln\frac{[A_{0}]}{[A_{t}]}=kt](https://tex.z-dn.net/?f=ln%5Cfrac%7B%5BA_%7B0%7D%5D%7D%7B%5BA_%7Bt%7D%5D%7D%3Dkt)
Where
A0 = initial concentration
At = concentration after time "t"
t = time
k = rate constant
For first order reaction the relation between rate constant and half life is:
Let us calculate k
k = 0.693 / 72 = 0.009625 years⁻¹
Given
At = 0.25 A0
time = 144 years
So after 144 years the sample contains 25% parent isotope and 75% daughter isotopes**
Simply two half lives
Answer:
answer is 12.18
Explanation:
(C2H5NH2, Kb = 5.6 x 10-4.)
Sodium, Atomic mass: 22.989769 g
You can see in a periodic table
