Final answer:
When 105.5 g of zinc reacts with excess HCl, it produces approximately 1.614 moles of H2 gas, based on the balanced equation Zn(s) + 2HCl(aq) → ZnCl2 (aq) + H2(g) and the molar mass of zinc being 65.4 g/mol.
Step-by-step explanation:
The student is asking how many moles of H2 gas will be produced when 105.5 g of zinc reacts with excess HCl. We begin by writing the balanced chemical equation for the reaction between zinc metal and hydrochloric acid:
Zn(s) + 2HCl(aq) → ZnCl2 (aq) + H2(g)
From the equation, we can see that 1 mole of zinc metal reacts with 2 moles of HCl to produce 1 mole of zinc chloride and 1 mole of H2 gas. Since the molar mass of zinc is approximately 65.4 g/mol, we divide the mass of zinc by its molar mass to calculate the moles of zinc.
To find the moles of H2 produced, we use the stoichiometric ratio from the balanced equation, which is a 1:1 ratio between zinc and hydrogen gas.
Calculation:
- Moles of zinc = mass of zinc / molar mass of zinc = 105.5 g / 65.4 g/mol = 1.614 moles (approximately)
- Moles of H2 = Moles of zinc (since it's a 1:1 ratio) = 1.614 moles of H2
Therefore, the reaction of 105.5 g of zinc with excess HCl would produce approximately 1.614 moles of H2 gas.