Question

a student forgot to include the 12 h2o when calculating the formula mass of the compound. how will the calculated percent yield be affected?

Answer 1

Forgetting to include the 12 H2O in formula mass calculations will result in a falsely high percent yield. Proper percent yields range from 0% to 100%, and accurate calculations are essential for true values.

Step-by-step explanation:

If a student forgets to include the 12 H2O when calculating the formula mass of a compound, their calculation of the formula mass will be significantly lower than it should be. Consequently, if they use this incorrect lower mass to calculate the percent yield, they would end up with a percent yield that is mistakenly higher than the actual value. At extremes, it might even exceed 100%, which is typically a clear sign of an error in calculation or the presence of impurities which might be solvents like water. The correct calculation of formula mass including the hydrate water is essential to accurately determine the percent composition of the compound and subsequently the percent yield from a given reaction.

It is important to recognize that proper percent yields are between 0% and 100%; yields greater than 100% usually point towards experimental errors or contaminants within the product. A high percent yield, for instance, 80%-90%, is generally deemed good to excellent, while a 50% yield is considered fair. Including all components such as water in hydrates is crucial for correct percent composition calculations.

Answer 2

If the student forgot to calculate 12 H2O molecule from the compound, that means the compound molecular mass used will be much lower than it should. If the molecular mass calculated lower than it should, then the percent yield would be increased.
If the student fixes the compound mass, then the yield will become lower than the first result.