Question

calculate the mass of sodium which contain the same number of atoms are present in 10 gram of magnesium

Answer 1

1000 mL of solution containing 0.375 moles of sodium acetate. ∴Number of moles of sodium acetate in 500 mL. Molar mass of sodium acetate = 82.0245 g mole–1 (Given) ∴ Required mass of sodium acetate = (82.0245 g mol–1)

Answer 2

The mass of the sodium is taken to be 'x' in the given pic.
See the attached pic.

Hope it helps u.