Calculate the mass of potassium hydroxide formed by the interaction of 3.9 g of potassium with excess water.

1. When potassium interacts with an excess of water, the following reaction occurs:

2K + 2H2O = 2KOH + H2 ↑;

2.calculate the chemical amount of potassium:

n (K) = m (K): M (K) = 3.9: 39 = 0.1 mol;

3.determine the amount of potassium hydroxide obtained:

n (KOH) = n (K) = 0.1 mol;

4.calculate the mass of the hydroxide:

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

M (KOH) = 39 + 16 + 1 = 56 g / mol;

m (KOH) = 0.1 * 56 = 5.6 g.

Answer: 5.6 g.