Calculate the mass and amount of sodium substance reacted with 128 g of sulfur.

Let’s execute the solution:

According to the condition of the problem, we write down the process equation:
Y -? m -?

2Na + S = Na2S – compounds, sodium sulfide was obtained;

m = 128 g

Calculations by formulas:
M (Na) = 22.9 g / mol;

M (S) = 32 g / mol;

Y (S) = m / M = 128/32 = 4 mol.

Proportion:
X mol (Na) – 4 mol (S);

-2 mol -1 mol from here, X mol (S) = 2 * 4/1 = 8 mol.

We find the mass of the original substance:
m (Na) = Y * M = 8 * 22.9 = 183.2 g

Answer: the mass of sodium is 183.2 g