21. __ A percent yield of 0 indicates: a. The reaction occurred too quickly b. No product was obtained c. All reactants were consumed d. The calculations were wrong

## Step 1<br />The percent yield is a measure of the efficiency of a chemical reaction. It is calculated by dividing the actual yield (the amount of product actually produced) by the theoretical yield (the amount of product that would be produced if the reaction were 100% efficient), and then multiplying by 100 to get a percentage.<br /><br />## Step 2<br />A percent yield of 0% indicates that no product was obtained from the reaction. This could be due to a variety of reasons, such as the reaction not occurring at all, or the product being completely lost during the process.<br /><br />## Step 3<br />The other options provided do not accurately describe a situation where the percent yield would be 0%. For example, a reaction occurring too quickly would not necessarily result in a 0% yield. Similarly, all reactants being consumed would typically result in a high yield, not a 0% yield. Lastly, incorrect calculations would not directly result in a 0% yield.