El número de Avogadro es 6,022 x 10^23, y es el número de átomos que hay en un mol de dicho elemento. A su vez un mol es la cantidad de un elemento cuya masa en gramos coincide con el peso atómico.
Por tanto, 6,022 x 10^23 átomos del elemento tienen una masa en gramos igual a su peso atómico. Hacemos una regla de tres:
1 gramo -------- 1,5 x 10^22 átomos
x ------------------ 6,022 x 10^23 átomos
=> x = 40,1 gramos por mol del elemento.
De modo que su peso atómico es 40,1. Se trata del calcio.
Saludos.
Answer:
60.8%
Explanation:
We'll begin obtaining the molar mass of cobalt(II) fluoride, CoF2. This can be done as shown below:
Molar mass of CoF2 = 59 + (19x2) = 97g/mol.
The percentage composition of cobalt in cobalt(II) fluoride, CoF2 is given by:
Mass of Co/Molar Mass of CoF2 x 100
=> 59/97 x 100 = 60.8%
Therefore, the percentage composition of cobalt in cobalt(II) fluoride, CoF2 is 60.8%
Answer:

Explanation:
A. Moles of Na
1 mol Na atoms = 5.60 × 10²³ atoms of Na

B. Moles of hydrogen
You haven't given the equation for the reaction. However, we can write an equation
2Na + 2HX ⟶ 2NaX+ H₂
n/mol: 0.930
1 mol of H₂ is formed from 2 mol of Na

The roots could no longer access depleted groundwater.
The topsoil in the area eroded.
XY₂ is the molecular formula of an ionic compound where X is magnesium (Mg) and Y is chloride (Cl) and magnesium is metal of second group of the periodic table and represents the 2nd group and chloride belongs to 17th group.
<h3>What are ionic compound?</h3>
Ionic compounds are those which completely dissociate into their constituent ions in water one is metal and other is non metal.
They complete their octave by sharing lone pair of electron and attend the positive and negative charge after dissociation are know as ionic compounds.
Therefore, the molecular formula of an ionic compound where X is magnesium (Mg) and Y is chloride (Cl) and magnesium is metal of second group of the periodic table and represents the 2nd group and chloride belongs to 17th group.
Learn more about ionic compound, here:
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