Answer:
The number of moles of Sr in one mole of Sr(HCO₃)₂ = 1 mole
The number of moles of H in one mole of Sr(HCO₃)₂ = 2 moles
The number of moles of C in one mole of Sr(HCO₃)₂ = 2 moles
The number of moles of O in one mole of Sr(HCO₃)₂ = 6 moles
Explanation:
The given chemical formula of the compound is Sr(HCO₃)₂
The number of atoms of Sr in the compound = 1
The number of atoms of H in the compound = 2
The number of atoms of C in the compound = 2
The number of atoms of O in the compound = 6
The number of atoms of each element present in each formula unit of Sr(HCO₃)₂ is proportional to the number of moles of each atom in one mole of Sr(HCO₃)₂
Therefore;
The number of moles of Sr in one mole of Sr(HCO₃)₂ = 1 mole
The number of moles of H in one mole of Sr(HCO₃)₂ = 2 moles
The number of moles of C in one mole of Sr(HCO₃)₂ = 2 moles
The number of moles of O in one mole of Sr(HCO₃)₂ = 6 moles.
<h3>
Answer:</h3>
63 years
Eighth
The number of half lives
<h3>
Explanation:</h3>
It will take 63 years for half of the sample to decay
In 189 years, eighth of the sample will be left
Scientists can figure out how old a sample is by multiplying the number of half lives by the length of the half life.
Half life is the time taken by a radioactive sample to decay to half of the original amount.
Therefore, for a radioactive element with a half-life of 63 years, it will take 63 years for the sample to decay to half of the original amount.
After 189 years, only an eighth of the sample will be left.
That is, 189 years is equivalent to 3 half-lives
Therefore, if the original amount is 1, then;
1 → 0.5 → 0.25 → 0.125
Thus, scientists can figure out how old a sample is by multiplying the number of half lives by the length of the half life.
<u>Answer:</u> The equation to calculate the mass of remaining isotope is ![[A]=\frac{20}{10^{-0.217t}}](https://tex.z-dn.net/?f=%5BA%5D%3D%5Cfrac%7B20%7D%7B10%5E%7B-0.217t%7D%7D)
<u>Explanation:</u>
The equation used to calculate rate constant from given half life for first order kinetics:
where,
= half life of the reaction = 
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
![[A_o]](https://tex.z-dn.net/?f=%5BA_o%5D)
= initial amount of the sample = 20 grams
[A] = amount left after decay process = ? grams
Putting values in above equation, we get:
![0.5=\frac{2.303}{t}\log\frac{20}{[A]}](https://tex.z-dn.net/?f=0.5%3D%5Cfrac%7B2.303%7D%7Bt%7D%5Clog%5Cfrac%7B20%7D%7B%5BA%5D%7D)
Hence, the equation to calculate the mass of remaining isotope is
Chemical equations are equations that show that the chemical formulas of a substance that has been reacted and/or produced.
