[Rvier]

Two questions related to % yield:

1. Calculate the % yield if 4 moles of ethylene are reacted with excess water to produce 3.8 moles of ethanol.

2. Thermal decomposition of potassium chlorate produces oxygen and potassium chloride. Calculate the % yield if 35 g of oxygen are collected after heating 100g of KClO3. 


(I know that % yield = actual yield / theoretical yield * 100%, but I'm unsure how to get the theoretical yield in both cases).

Any assistance on setting up these problems would be appreciated.

[JGK]

Write the balanced chemical equation in each case.

This gives you the molar reationship between the starting materials and products

[Rvier]

Okay, so for #1 the equation is C₂H₄ + H₂O ---> C₂H₆O, and for #2 the equation is 2 KClO₃ ---> 2 KCl + 3 O₂.

[Borek]

So it is simple stoichiometry now.