What Is Percent Yield And How To Calculate It? (With Examples)

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When we take pharmaceuticals to restore our health, we rarely consider the intricate processes that led to their creation. Before a small white pill can effectively alleviate a headache in just hours, a series of complex chemical processes occur, all meticulously supervised by trained chemists.

Throughout the manufacturing process, various chemical reactions yield specific amounts of usable products. After these reactions, chemists utilize a formula known as percent yield to compare the theoretical amount of product that could have been produced against the actual amount obtained.

Key Takeaways:

Percent yield indicates the percentage of actual results compared to expected results, reflecting the overall success of a chemical reaction.
The formula for calculating percent yield is: (Actual Yield / Theoretical Yield) X 100 = Percent Yield.
This metric is crucial in chemistry for assessing the efficacy of chemical reactions in practice versus theoretical predictions.
Percent yield can also be leveraged in various fields to measure actual outcomes against projections.

What Is Percent Yield And How To Calculate It? (With Examples)

In This Article

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What Is Percent Yield?
Why Is Percent Yield Important?
What Is Theoretical Yield?
How to Calculate Percent Yield
Examples of Calculating Percent Yield
Final Thoughts
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What Is Percent Yield?

Percent yield is a vital formula used by chemists to evaluate the outcomes of chemical reactions. Each reaction has an expected outcome, but it is common for the actual results to deviate from these predictions.

The percent yield formula provides chemists with a percentage that reflects the success of a reaction compared to the anticipated results.

The formula for percent yield is:

(Actual Yield / Theoretical Yield) X 100 = Percent Yield

Why Is Percent Yield Important?

Beyond understanding chemical reactions, the percent yield formula holds significant importance in various fields, such as finance. Companies that produce chemical products rely on this metric to assess their productivity and financial efficiency in the manufacturing process.

A low percent yield indicates a significant discrepancy from the expected results, suggesting inefficiencies in production. Such inefficiencies can lead to financial losses and wasted resources, making it critical for companies to strive for improved percent yields.

What Is Theoretical Yield?

Theoretical yield refers to the maximum possible amount of product that can result from a chemical reaction, as determined by stoichiometric calculations. However, in practice, actual chemical reactions rarely achieve these predicted amounts due to factors like experimental errors, side reactions, or incomplete reactions. Companies involved in chemical production have a vested interest in minimizing these discrepancies to maximize their yield.

How to Calculate Percent Yield

With a foundational understanding of percent yield, let’s break down the calculation process step-by-step.

Understand the formula. To solve any mathematical problem, including those in chemistry, start with the formula. While mathematical formulas can seem daunting, they become manageable when analyzed piece by piece.

In the percent yield formula, the two necessary values are the actual yield and the theoretical yield.
Find the actual yield. The actual yield is the quantity achieved from the chemical reaction, regardless of expected outcomes.
Determine the theoretical yield. Theoretical yield represents the expected quantity following a reaction, defined as the maximum anticipated result.

This can vary depending on the specific chemical medium used, such as the duration a substance takes to react under certain conditions. Research can help uncover the theoretical yield for specific reactions.
Divide the actual yield by the theoretical yield. Once you have both values, the next step is straightforward. Place the actual yield over the theoretical yield and perform the division to obtain a decimal representing the unrefined percent yield.
Multiply by 100. To convert the decimal into a percentage, multiply the result by 100. This yields the final percent yield.

Examples of Calculating Percent Yield

Percent Yield Example 1:

A chemist is studying the reaction of potassium carbonate (K₂CO₃) to produce soap for a large manufacturer. In this test, he measures how long the compound takes to dissolve under a heat lamp set to 37 degrees Celsius.

The theoretical yield of this reaction is 17 minutes. However, when the experiment is conducted, the actual yield is found to be 13.2 minutes. He calculates the percent yield to report on the process’s efficiency.

Using the percent yield formula:

(Actual Yield / Theoretical Yield) X 100 = Percent Yield

He inputs the values:

(13.2 / 17) X 100 = Percent Yield

Dividing gives 0.776, the unrefined percent yield.

Multiplying this by 100 results in a percent yield of 77.6%.

What it means: In a laboratory setting, achieving the theoretical maximum yield is challenging. Generally, any percent yield above 60% is considered effective. With a yield of 77.6%, this reaction demonstrates strong productivity.

Percent Yield Example 2:

A major healthcare company produces hydrogen peroxide (H2O2), a compound utilized for cleaning small wounds. The company investigates the decomposition of hydrogen peroxide to assess process effectiveness.

The theoretical yield for this reaction is 54.3. The actual yield measured during the reaction is 23.7. The chemist applies the percent yield formula:

(23.7 / 54.3) X 100 = Percent Yield

Dividing yields an unrefined percent yield of 0.436. Multiplying by 100 gives a percent yield of 43.6%.

What it means: This percent yield falls below the 60% threshold for positive productivity. While not ideal, it is important to note that a yield below 40% is typically deemed unacceptable in terms of efficiency. Thus, while 43.6% is close to this threshold, it remains within an acceptable range.

Final Thoughts

Percent yield plays a crucial role in chemical manufacturing worldwide. As this figure decreases, companies face increased material waste and inefficiencies in production.

It’s worth noting that while actual yield is usually less than theoretical yield, situations can arise where percent yield exceeds 100%. This anomaly often indicates issues like impure reactants or unexpected side reactions, which can be just as detrimental to manufacturers as a low yield.

Even outside the realm of chemistry, understanding production costs and their impacts on the bottom line can enhance your contributions to your team.

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Author

Sky Ariella

Sky Ariella is a professional freelance writer, originally from New York. She has been featured on websites and online magazines covering topics in career, travel, and lifestyle. She received her BA in psychology from Hunter College.

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