Answer to Question #140124 in Chemistry for Jamila

Question

4g of sodium is reacted with excess oxygen to make sodium oxide. Work out the mass of sodium oxide produced.

Answer 1

Solution:

The balanced chemical reaction:

4Na + O₂ = 2Na₂O

According to the chemical reaction: Moles of Na / 4 = Moles of Na₂O / 2

n(Na)/2 = n(Na₂O)

n(Na) = Mass of Na / Molar mass of Na

The molar mass of Na is 23 g mol^-1.

n(Na) = 4g / 23 g mol^-1 = 0.1739 mol

Hence,

n(Na₂O) = n(Na)/2 = 0.1739 mol / 2 = 0.08695 mol.

n(Na₂O) = Mass of Na₂O / Molar mass of Na₂O

The molar mass of Na₂O is 62 g mol^-1.

m(Na₂O) = n(Na₂O) × M(Na₂O) = 0.08695 mol × 62 g mol^-1 = 5.3909 g = 5.4 g

m(Na₂O) = 5.4 g

Answer: 5.4 grams of sodium oxide (Na₂O) produced.