Explanation:
1) Initial mass of the Cesium-137=
= 180 mg
Mass of Cesium after time t = N
Formula used :
Half life of the cesium-137 =
= initial mass of isotope
N = mass of the parent isotope left after the time, (t)
= half life of the isotope
= rate constant
![N=N_o\times e^{-(\frac{0.693}{t_{1/2}})\times t}](https://tex.z-dn.net/?f=N%3DN_o%5Ctimes%20e%5E%7B-%28%5Cfrac%7B0.693%7D%7Bt_%7B1%2F2%7D%7D%29%5Ctimes%20t%7D)
Now put all the given values in this formula, we get
Mass that remains after t years.
![N=180 mg\times e^{0.0231 year^{-1}\times t}](https://tex.z-dn.net/?f=N%3D180%20mg%5Ctimes%20e%5E%7B0.0231%20year%5E%7B-1%7D%5Ctimes%20t%7D)
Therefore, the parent isotope remain after one half life will be, 100 grams.
2)
t = 70 years
![N_o=180 mg](https://tex.z-dn.net/?f=N_o%3D180%20mg)
![t_{1/2}= 30 yeras](https://tex.z-dn.net/?f=t_%7B1%2F2%7D%3D%2030%20yeras)
N = 35.73 mg
35.73 mg of cesium-137 will remain after 70 years.
3)
![N_o=180 mg](https://tex.z-dn.net/?f=N_o%3D180%20mg)
![t_{1/2}= 30 yeras](https://tex.z-dn.net/?f=t_%7B1%2F2%7D%3D%2030%20yeras)
N = 1 mg
t = ?
![\frac{-30 year}{0.693}\times \ln \frac{1 mg}{180 mg}=t](https://tex.z-dn.net/?f=%5Cfrac%7B-30%20year%7D%7B0.693%7D%5Ctimes%20%5Cln%20%5Cfrac%7B1%20mg%7D%7B180%20mg%7D%3Dt)
t = 224.80 years ≈ 225 years
After 225 years only 1 mg of cesium-137 will remain.
There are ALOT because they would always come in and out and they will burst which creates more so techneclly there are infinate
Answer:
The correct option is;
It contains 6.02 × 10²³ particles of a given substance
Explanation:
A mole of substance is the standard scientific unit of measurement for the quantity of the substance which is made up of a large number of small particles such as molecules, ions, atoms, electrons or other entities.
The General Conference on Weights and Measures defines the mole as the amount of a substance that contains 6.02214076 × 10²³ units of entities
The number 6.02214076 × 10²³, is also known as Avogadro's number.
<span>thermal energy
hope this helped</span>
The name of the chemical made of 14 g Lithium or 2 moles
Lithium, 32 g Sulfur or 1 mol sulfur and 64 g oxygen or 4 moles of oxygen is
Lithium sulfate. From the chemical reation:
<span>2Li + S + 4O > Li2SO4</span>