To solve this problem, we'll follow these steps:
1. Convert the mass of substance A to moles.
2. Determine the number of moles of substance B using the stoichiometric ratio.
3. Convert the number of moles of substance B to molecules.
Step 1: Convert the mass of A to moles
Given:
Mass of substance A = 29.5 g
Molar mass of substance A = 15.7 g/mol
Number of moles of A = Mass of A / Molar mass of A
Number of moles of A = 29.5 g / 15.7 g/mol
Number of moles of A ≈ 1.875 mol
Step 2: Determine the number of moles of substance B using the stoichiometric ratio
The given ratio states that 2 moles of A react to produce 3 moles of B.
Number of moles of B = (Number of moles of A) * (Moles of B / Moles of A)
Number of moles of B = 1.875 mol * (3 mol B / 2 mol A)
Number of moles of B ≈ 2.8125 mol
Step 3: Convert the number of moles of substance B to molecules
To convert moles to molecules, we need to use Avogadro's number, which states that 1 mole of any substance contains approximately 6.022 x 10^23 molecules.
Number of molecules of B = (Number of moles of B) * (Avogadro's number)
Number of molecules of B = 2.8125 mol * (6.022 x 10^23 molecules/mol)
Number of molecules of B ≈ 1.691 x 10^24 molecules
Therefore, when 29.5 g of substance A reacts, approximately 1.691 x 10^24 molecules of substance B are produced.