Question

Zn + 2hcl = zncl2 + h2 найти массу h2, если масса 2hcl = 142г

Answer 1

Ответ: масса Н2=4 грамма.

Answer 2

To find the mass of H2 produced in the reaction between Zn and 2HCl, we need to use stoichiometry and the molar mass of H2.

The balanced chemical equation for the reaction is:

Zn + 2HCl → ZnCl2 + H2

According to the equation, 1 mole of Zn reacts with 2 moles of HCl to produce 1 mole of H2. Therefore, we need to first find the number of moles of HCl in 142g of 2HCl.

Molar mass of 2HCl = 2(1.008 + 35.45) = 73.92 g/mol

Number of moles of 2HCl = Mass / Molar mass = 142 g / 73.92 g/mol = 1.918 mol

Since the stoichiometry of the reaction is 1:2 (Zn : 2HCl), the number of moles of H2 produced is half of the number of moles of HCl, i.e., 0.959 mol.

The molar mass of H2 is 2.016 g/mol. Therefore, the mass of H2 produced is:

Mass of H2 = Number of moles of H2 x Molar mass of H2 = 0.959 mol x 2.016 g/mol = 1.935 g

Therefore, the mass of H2 produced in the reaction is 1.935 g.