Balanced Equation:
The decomposition of potassium chlorate (KClO₃) produces oxygen gas (O₂):
2KClO₃→2KCl+3O₂
Given:
Desired yield of O₂= 4.00 g
Percent yield = 65.0%
Step 1: Calculate Theoretical Yield of O₂ :
The theoretical yield is the amount of product that should be obtained in an ideal scenario.
From the balanced equation:
2 moles of KClO₃ produce 3 moles of O₂.
Calculate the molar mass of O2: 32.00g/mol (Oxygen)
Use the molar mass to convert grams of O₂ to moles:
Moles of O₂=Mass/Molar mass=4.00 g/32.00g/mol=0.125mol
Calculate Theoretical Yield:
From the balanced equation, 2 moles of KClO₃ produce 3 moles of O₂.
If 3 moles of O₂ require 2 moles of KClO₃, then 0.125 moles of O₂ require:
Moles of KClO₃=0.125mol O₂×2 mol KClO₃/3 mol O₂=0.0833 mol KClO₃
Step 2: Calculate Mass of KClO₃ Needed (with Percent Yield):
The actual yield is 65.0% of the theoretical yield.
Calculate Theoretical Yield:
Theoretical Yield=Moles of KClO₃×Molar mass of KClO₃
Theoretical Yield=0.0833mol×Molar mass of KClO₃
Calculate Mass of KClO₃ (with Percent Yield):
Percent Yield=Actual Yield/Theoretical Yield×100
Given the Percent Yield = 65.0%, rearrange the equation to find the Actual Yield.
Rearranged equation for Actual Yield:
Actual Yield=Percent Yield/100×Theoretical Yield
Substitute the given values to find the Actual Yield.
Calculate Actual Mass of KClO₃:
Actual Mass of KClO₃=Actual Yield=65.0/100×Theoretical Yield
This calculation will yield the mass of KClO₃ needed to produce 4.00 grams of O₂ with a percent yield of 65.0%.