Question

how many atoms are present in 120 u of calcium?

Answer 1

mass of 1 calcium atom = 40u
number of atoms present in 120u = 120/40 = 3 atoms.

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If you want to find the number of atoms in 120g of calcium,
then multiply it with avogadro number.

number of atoms in 120g calcium = 3×(6.022×10²³) = 1.8066 × 10²⁴ atoms

Answer 2

Answer:

The number of atoms present in 120u of calcium

$= 1.8066 * 10^{24}$ atoms.

Explanation:

The number of units in one mole of any substance that exists is named Avogadro’s number or Avogadro’s constant. It exists equivalent to $6.022140857*10^{23}$. The units may be electrons, ions, atoms, or molecules, depending on the nature of the reaction and the nature of the substance.

Mass of 1 calcium atom $= 40u$

Number of atoms present in $120u = 120/40= 3 atoms.$

If you want to find the number of atoms in $120g$ of calcium,

then multiply it with Avogadro number.

number of atoms in 120g calcium$= 3*(6.022*10^{23} )$

$= 1.8066 * 10^{24}$ atoms

Therefore, the number of atoms present in 120u of calcium

$= 1.8066 * 10^{24}$ atoms.

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