Library / Foundations: Chemistry / FCH-08
Foundations: Chemistry
Percentage yield
How much product was actually made compared with the maximum possible.
- Ref
- FCH-08
- Rev
- v1
- Field
- Foundations: Chemistry
- Result
- % [%]
Actual and theoretical yield must be in the same unit (mass or moles). The theoretical yield comes from the balanced equation.
It compares what you really got with what the equation says you should get at best.
Calculator
%
g
g
- Product lost1.4 g
- Yield as a fraction0.75
What drives the result
Each variable is moved across its typical range while the others stay at the values above. The longest bar is the key driver.
Percentage yield (%) current value 75 %
theoreticalTheoretical yieldKey driver
0.4242,000
actualActual yield
0.17917,900
- A yield above 100% means the product is impure or still wet.
- Losses in separate steps multiply, so a five-step synthesis at 80% each yields only about 33% overall.
Chart data as tables
Ranked variables
| Variable | Typical range | Lowest result | Highest result | Swing (%) | Local step | Change in result |
|---|---|---|---|---|---|---|
| theoretical Theoretical yield | 0.01 to 1,000 g | 0.42 | 42,000 | 42,000 | +10% | −9.09 % |
| actual Actual yield | 0.01 to 1,000 g | 0.1786 | 17,860 | 17,860 | +10% | +10 % |
Sweep of Actual yield
| Actual yield (g) | Percentage yield (%) |
|---|---|
| 0.01 | 0.1786 |
| 0.04217 | 0.753 |
| 0.1778 | 3.175 |
| 0.7499 | 13.39 |
| 3.162 | 56.47 |
| 13.34 | 238.1 |
| 56.23 | 1,004 |
| 237.1 | 4,235 |
| 1,000 | 17,860 |
Sweep one variable
Percentage yield (%)Hover, touch, or use the arrow keys on the chart
Variables and how each one contributes
%
Percentage yield
What the equation gives you. Everything else feeds it.
actual
Actual yield
Mass of product collected. Directly proportional.
theoretical
Theoretical yield
Maximum mass from the equation. Inversely proportional.
Worked example with the values above
- Ratio: 4.2 / 5.6 = 0.75.
- Multiply by 100.
- Percentage yield = 75 %.
Assumptions and limits
- Same substance counted in both numbers.
- Theoretical yield based on the limiting reagent.
Common mistakes
- Comparing grams with moles.
- Using the wrong reagent for the theoretical yield.
Statistics and uncertainty
Weighing errors matter more when the quantity is small; 0.01 g on 4.20 g is only 0.2%.
Where it is used
- Process efficiency in manufacturing.
- Comparing synthesis routes.
Maths you need
- Reacting masses: theoretical yield
- Percentages: part over whole