Question

Small quantities of hydrogen gas can be prepared in the lab by addition of hydrochloric acid to zinc. The gas is typically collected over water. What volume of hydrogen can be collected from 0.625g Zn

Answer 1

Answer:

0.214 L

Explanation:

Step 1: Write the balanced equation

This is a single displacement reaction.

Zn(s) + 2 HCl(aq) ⇒ ZnCl₂(aq) + H₂(g)

Step 2: Calculate the moles corresponding to 0.625 g of Zn

The molar mass of Zn is 65.38 g/mol.

0.625 g × 1 mol/65.38 g = 9.56 × 10⁻³ mol

Step 3: Calculate the moles of H₂ produced from 9.56 × 10⁻³ moles of Zn

The molar ratio of Zn to H₂ is 1:1. The moles of H₂ produced are 1/1 × 9.56 × 10⁻³ mol = 9.56 × 10⁻³ mol.

Step 4: Calculate the volume occupied by 9.56 × 10⁻³ moles of hydrogen

Assuming standard pressure and temperature, 1 mole of hydrogen occupies 22.4 L.

9.56 × 10⁻³ mol × 22.4 L/1 mol = 0.214 L