Answer:
0.15g
Step-by-step explanation:
Given parameters:
Mass of Zn = 5g
Unknown:
Mass of hydrogen gas = ?
Solution:
To solve this problem, we must first write the reaction expression;
Zn + 2HCl → ZnCl₂ + H₂
Now find the number of moles of the known specie which is Zn;
Number of moles of Zn =

Molar mass of Zn = 65.4g/mol
Number of moles of Zn =
= 0.08mole
1 mole of Zn will produce 1 mole of H₂
0.08 mole of Zn will give 0.08 mole of H₂
Mass of H₂ = number of moles x molar mass
molar mass of H₂ = 2(1) = 2g/mol
Mass of H₂ = 0.08mol x 2g/mol = 0.15g