To determine the mass of magnesium containing the same number of atoms as 2g of calcium, we need to use the concept of mole and Avogadro's number.



Avogadro's number is defined as the number of particles (atoms, molecules, or ions) in one mole of a substance. It has the value of 6.022 x 10^23 particles per mole.



Molar mass is the mass of one mole of a substance. It is expressed in grams per mole (g/mol).



To calculate the mass of magnesium containing the same number of atoms as 2g of calcium, we need to follow these steps:

1. Find the number of moles of calcium in 2g of calcium.

- Molar mass of calcium = 40.08 g/mol
- Number of moles of calcium = mass/molar mass
- Number of moles of calcium = 2g/40.08 g/mol
- Number of moles of calcium = 0.0499 mol

2. Find the number of atoms of calcium in 2g of calcium.

- Number of atoms of calcium = number of moles x Avogadro's number
- Number of atoms of calcium = 0.0499 mol x 6.022 x 10^23 particles/mol
- Number of atoms of calcium = 3.00 x 10^22 atoms

3. Find the number of atoms of magnesium that is equal to the number of atoms of calcium.

- Since magnesium and calcium have different atomic masses, we need to use the concept of the mole ratio.
- The mole ratio is the ratio of the number of moles of one substance to the number of moles of another substance in a chemical equation.
- The chemical formula of magnesium is Mg and its atomic mass is 24.31 g/mol.
- The mole ratio of magnesium to calcium is 1:1 since they have the same number of atoms.
- Therefore, the number of atoms of magnesium is also 3.00 x 10^22 atoms.

4. Find the mass of magnesium containing the same number of atoms as 2g of calcium.

- Molar mass of magnesium = 24.31 g/mol
- Number of moles of magnesium = number of atoms/Avogadro's number
- Number of moles of magnesium = 3.00 x 10^22 particles/6.022 x 10^23 particles/mol
- Number of moles of magnesium = 0.0499 mol
- Mass of magnesium = number of moles x molar mass
- Mass of magnesium = 0.0499 mol x 24.31 g/mol
- Mass of magnesium = 1.21g

Therefore, the mass of magnesium containing the same number of atoms as 2g of calcium is 1.21g.

40 g contains na Can atoms
so 2 g contains na /20 atoms

na atoms of Mg is present in 24 g
so na/20 atoms is present in (24/na)×(na/20)=1.2g