Mass of Mg=3 g
Further explanation
The mole is the number of particles contained in a substance
1 mol = 6.02.10²³
mol Mg in 7.43 x 10²² atoms :
[tex]\tt \dfrac{7.43\times 10^{22}}{6.02\times 10^{23}}=0.1234[/tex]
mass Mg
[tex]\tt mass=mol\times MW\\\\mass=0.1234\times 24.3=2.99\approx 3[/tex]
