Answer:
25.1 g
Explanation:
Step 1: Write the balanced decomposition reaction
2 HBr(aq) ⇒ H₂(g) + Br₂(l)
Step 2: Calculate the moles corresponding to 24.7 g of Br₂
The molar mass of Br₂ is 159.81 g/mol.
24.7 g × 1 mol/159.81 g = 0.155 mol
Step 3: Calculate the moles of HBr needed to produce 0.155 moles of Br₂
The molar ratio of HBr to Br₂ is 2:1. The moles of HBr needed are 2/1 × 0.155 mol = 0.310 mol.
Step 4: Calculate the mass corresponding to 0.310 moles of HBr
The molar mass of HBr is 80.91 g/mol.
0.310 mol × 80.91 g/mol = 25.1 g
