Using the reaction equation: Zn (OH) 2 = ZnO + H2O, determine the mass of zinc oxide

Using the reaction equation: Zn (OH) 2 = ZnO + H2O, determine the mass of zinc oxide, which is formed during the decomposition of 19.8 g of the starting material.

Let us write the reaction equation for the thermal decomposition of zinc hydroxide:

Zn (OH) 2 (t) = ZnO + H2O

Let’s find the amount of zinc hydroxide substance:

v (Zn (OH) 2) = m (Zn (OH) 2) / M (Zn (OH) 2) = 19.8 / 99 = 0.2 (mol).

According to the reaction equation, 1 mol of ZnO is formed from 1 mol of Zn (OH) 2, therefore:

v (ZnO) = v (Zn (OH) 2) = 0.2 (mol).

Thus, the mass of the resulting zinc oxide:

m (ZnO) = v (ZnO) * M (ZnO) = 0.2 * 81 = 16.2 (g).

Answer: 16.2 g.