Answer:
16.7 days
Explanation:
We are given;
A radioactive isotope Iodine-131`
The decay rate is 0.138 d⁻¹
The percent decayed is 90%
We are suppose to calculate the number of days for the decay.
![In(\frac{[A_{0}]}{[A]})=kt](https://tex.z-dn.net/?f=In%28%5Cfrac%7B%5BA_%7B0%7D%5D%7D%7B%5BA%5D%7D%29%3Dkt)
Where, ![[A_{0}]](https://tex.z-dn.net/?f=%5BA_%7B0%7D%5D)
is the initial concentration and ![[A]](https://tex.z-dn.net/?f=%5BA%5D)
is the new concentration.
![t=In(\frac{[A_{0}]}{[A]})/k](https://tex.z-dn.net/?f=t%3DIn%28%5Cfrac%7B%5BA_%7B0%7D%5D%7D%7B%5BA%5D%7D%29%2Fk)
Assuming the initial concentration is x, then the final concentration after 90% decay will be 0.10x
Therefore;
![t=In(\frac{[x]}{[0.10x]})(\frac{1}{0.138})](https://tex.z-dn.net/?f=t%3DIn%28%5Cfrac%7B%5Bx%5D%7D%7B%5B0.10x%5D%7D%29%28%5Cfrac%7B1%7D%7B0.138%7D%29)
![t=In(\frac{[1]}{[0.10]})(\frac{1}{0.138})](https://tex.z-dn.net/?f=t%3DIn%28%5Cfrac%7B%5B1%5D%7D%7B%5B0.10%5D%7D%29%28%5Cfrac%7B1%7D%7B0.138%7D%29)
Time = 16.7 days
Therefore, it will take 16.7 days for 90% of I-131 to decay to Xe-131
Answer:
False
Explanation:
When electrons move from lower to higher electron energy level they absorb the energy. When they move from higher to lower energy level they emit energy.
Answer:
V₂ = 104.76 mL
Explanation:
Given data:
Initial volume = 100.0 mL
Initial temperature = 21°C (21 + 273.15 K = 294.15 K)
Final temperature = 35°C (35 + 273.15 K = 308.15 k)
Final volume = ?
Solution:
Charles Law:
According to this law, The volume of given amount of a gas is directly proportional to its temperature at constant number of moles and pressure.
Mathematical expression:
V₁/T₁ = V₂/T₂
V₁ = Initial volume
T₁ = Initial temperature
V₂ = Final volume
T₂ = Final temperature
Now we will put the values in formula.
V₁/T₁ = V₂/T₂
V₂ = V₁T₂/T₁
V₂ =100.0 mL × 308.15 K / 294.15 K
V₂ = 30815 mL.K /294.15 K
V₂ = 104.76 mL
No because most of them are forces
Three mole ratios can be written for a chemical reaction involving three substances
