As a result of the reaction of sodium oxide with water, 80 g of a 10% alkali solution were obtained.

As a result of the reaction of sodium oxide with water, 80 g of a 10% alkali solution were obtained. Determine the mass of sodium oxide reacted.

1. Let’s compose the equation for the reaction of sodium oxide with water:

Na2O + H2O = 2NaOH.

2. Let’s calculate the mass of the obtained sodium hydroxide:

m (NaOH) = w (NaOH) * m (solution) = 0.1 * 80 = 8 g.

3. Calculate the chemical amount of hydroxide:

n (NaOH) = m (NaOH): M (NaOH);

M (NaOH) = 23 + 16 + 1 = 40 g / mol;

n (NaOH) = 8: 40 = 0.2 mol.

4. Set the amount of reacted sodium oxide:

n (Na2O) = n (NaOH): 2 = 0.2: 2 = 0.1 mol.

5. Determine the mass of sodium oxide:

m (Na2O) = n (Na2O) * M (Na2O);

M (Na2O) = 2 * 23 + 16 = 62 g / mol;

m (Na2O) = 0.1 * 62 = 6.2 g.

Answer: 6.2 g.