A sample of sodium reacts completely with 0.213 kg of chlorine, forming 351 g of sodium chloride. What mass of sodium reacted?

Sodium reacts with chlorine as shown in the equation below;

2Na (s) + Cl2 (g) = 2NaCl (s)

The molar mass of sodium chloride is 58.44g/mol,

while that of sodium is 23 g/mol.

The moles of sodium cholride formed will be 351 g / 58.44 g = 6.006 moles

The mole ratio of sodium to Sodium chloride is 2 : 2,

therefore the moles of sodium used will be 6.006 moles,

Hence, mass of sodium used, 6.006 * 23 = 138.142 g or 0.1381 kg