The given mole ratio is 2:1 for O₂ to KClO₃. This means that for every 2 moles of O₂ produced, 1 mole of KClO₃ must be decomposed.
To find the number of moles of KClO₃ that must be decomposed when 5.00g of O₂ is produced, we need to set up a proportion using the molar mass of KClO₃.
The molar mass of KClO₃ can be calculated as follows:
K (39.10 g/mol) + Cl (35.45 g/mol) + O₃ (16.00 g/mol × 3) = 122.55 g/mol
Now, set up the proportion:
2 moles O₂ / 1 mole KClO₃ = 5.00 g O₂ / x moles KClO₃
Cross-multiply and solve for x:
2 moles O₂ × x moles KClO₃ = 5.00 g O₂ × 1 mole KClO₃
2x = 5.00 g O₂ × 1 mole KClO₃
2x = 5.00 g O₂ / 122.55 g/mol
2x = 0.0408 mol O₂
Now, solve for x:
x = 0.0408 mol O₂ / 2
x = 0.0204 mol KClO₃
Therefore, 0.0204 moles of KClO₃ must be decomposed when 5.00g of O₂ is produced.