Respuesta :
To calculate the number of atoms of any compound it is necessary to use the Avogadro constant. This is a constant of proportion between the amount of matter and the number of entities that are linked to that amount. These entities can be atoms, molecules, ions, electrons, protons, neutrons. The value of the Avogrado constant is 6.022 x 10^23 mol^-1.
So to calculate the number of atoms in 275 grams of iron (III) hydroxide:
- First you need to transform grams into moles
- transform moles into atoms/molecule using Avogrado constant.
- To transform 275 grams of Fe(OH)₃ you need to use the molecular mass of Fe(OH)₃ and the following equation: mole = mass/molar mass
Molecular mass of Fe(OH)₃:
Fe - 55.85
O - 16
H - 1
(1x55.85) + (3x16) + (3x1) = 106.86 g/mol
Replace the value in the equation:
mole = 250/106.86
mole = 2.34 mole of Fe(OH)₃
- Now, let's solve the number of molecules of Fe(OH)₃ into 2.34 mole of Fe(OH)₃:
6.022 x 10^23 molecule --- 1 mol
x molecule ---- 2.34 mole
x = 1.41 x 10^24 molecules of Fe(OH)₃
Answer: There are 1.41 x 10^24 molecules of Fe(OH)₃
