The percent yield tells us what proportion of starting material will be reacted to form product.
Both reactions have a percent yield less than 100%. This means that only a fraction of the first reactant will become reactant for the second reaction. Then, only a fraction of that fraction will be reacted to form the final product.
First convert the percentage yield to proportions:
0.227 for H → U and 0.241 for U → O
All of the starting materials (represented by the proportion 1), multiplied by the first fraction, gives the fraction of original material that becomes U:
1 * 0.227 = 0.227
We know that out of whatever quantity of material we feed into the second reaction 0.241 of that quantity will react to form O. Since we only got 0.227 U out of our original quantity of H, we multiply 0.227 by 0.241 to give the proportion of the original material, H, that yields O:
0.227 * 0.241 = .0553
Be sure to convert back to percentage:
.0553 * 100% = 5.53%
