Answer:
3.125 grams.
Explanation:
- It is known that the decay of a radioactive isotope isotope obeys first order kinetics.
- Half-life time is the time needed for the reactants to be in its half concentration.
- If reactant has initial concentration [A₀], after half-life time its concentration will be ([A₀]/2).
- Also, it is clear that in first order decay the half-life time is independent of the initial concentration.
∵ Thulium-167 has a half life of 9.0 days.
∴ The time is needed to calculate the grams are left after (36.0 days) represents (36.0 days / 9.0 days) = 4.0 half-lives.
50.0 grams → (first half life) 25.0 grams → (second half life) 12.5 grams → (third half life) 6.25 grams → (fourth half life) 3.125 grams.
So, the grams are left after 36.0 days = 3.125 grams.
B. because the other options are different sciences (biology and entomology)
This is an incomplete question, here is a complete question.
A 0.130 mole quantity of NiCl₂ is added to a liter of 1.20 M NH₃ solution. What is the concentration of Ni²⁺ ions at equilibrium? Assume the formation constant of Ni(NH₃)₆²⁺ is 5.5 × 10⁸
Answer : The concentration of 
ions at equilibrium is, 
Explanation : Given,
Moles of 
= 0.130 mol
Volume of solution = 1 L
Concentration of = Concentration of = 0.130 M
Concentration of 
= 1.20 M
The equilibrium reaction will be:
![Ni^{2+}(aq)+6NH_3(aq)\rightarrow [Ni(NH_3)_6]^{2+}](https://tex.z-dn.net/?f=Ni%5E%7B2%2B%7D%28aq%29%2B6NH_3%28aq%29%5Crightarrow%20%5BNi%28NH_3%29_6%5D%5E%7B2%2B%7D)
Initial conc. 0.130 1.20 0
At eqm. x [1.20-6(0.130)] 0.130
= 0.42
The expression for equilibrium constant is:
![K_f=\frac{[Ni(NH_3)_6^{2+}]}{[Ni^{2+}][NH_3]^6}](https://tex.z-dn.net/?f=K_f%3D%5Cfrac%7B%5BNi%28NH_3%29_6%5E%7B2%2B%7D%5D%7D%7B%5BNi%5E%7B2%2B%7D%5D%5BNH_3%5D%5E6%7D)
Now put all the given values in this expression, we get:
Thus, the concentration of ions at equilibrium is,
This is not a question kid
Nuclear reaction involves two reacting particles a heavy target nucleus and a light bombarding particle and produces two new particles a heavier product nucleus and a lighter ejected particle.
