Answer:

Explanation:
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In this case, since the radioactive reaction for the alpha emission of astatine-218 to bismith-214 involve the release of a helium atom as shown below:

Whereas the atomic number decreases by 2 and the mass number by 4 in agreement to the release of the Helium atom.
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The main constituent of gallstones is cholesterol. Cholesterol may have a role in heart attacks and blood clot formation. Its elemental percentage composition is 83.87% C, 11.99% H, and 4.14% O. It has a molecular weight of 386.64 amu. Empirical formula is C₃H₄O₁ and Molecular formula is 7(C₃H₄O₁).
<h3>What is Empirical Formula ?</h3>
Empirical formula is the simplest whole number ratio of atoms present in given compound.
Element % Atomic mass Relative no. of atoms Simplest whole ratio
C 83.87 12
= 6.98
= 3
H 11.99 1
= 11.09
= 4
O 4.14 16
= 0.25
= 1
Thus the empirical formula is C₃H₄O₁.
<h3>How to find the Molecular formula of compound ?</h3>
Molecular formula = Empirical formula × n
n = 
= 
= 7
Molecular formula = Empirical formula × n
= 7 (C₃H₄O₁)
Thus from the above conclusion we can say that The main constituent of gallstones is cholesterol. Cholesterol may have a role in heart attacks and blood clot formation. Its elemental percentage composition is 83.87% C, 11.99% H, and 4.14% O. It has a molecular weight of 386.64 amu. Empirical formula is C₃H₄O₁ and Molecular formula is 7(C₃H₄O₁).
Learn more about the Empirical Formula here: brainly.com/question/1603500
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Answer:
19.6 g is the mass of methanol
Explanation:
Density of methanol is 0.787 g/mL.
Density means mass / volume
Methanol density = Methanol mass / Methanol volume.
Let's replace in the formula
0.787 g/mL = Methanol mass / 25 mL
0.787 g/mL . 25 mL = Methanol mass → 19.6 g
I hate stoichiometry. I will help you but I need to know the question first.