A student found the mass of camphor to be 162.5 g. The actual mass of camphor is 152.23 g. What is the percent error of this experiment?
A) 106.7%
B) 6.320%
C) 93.68%
D) 6.746%
The correct answer and explanation is:
To calculate percent error, we use the formula: Percent Error=∣Measured Value−Actual ValueActual Value∣×100\text{Percent Error} = \left| \frac{\text{Measured Value} – \text{Actual Value}}{\text{Actual Value}} \right| \times 100
Given:
- Measured value (experimental value) = 162.5 g
- Actual value (true value) = 152.23 g
Step 1: Subtract actual from measured
162.5−152.23=10.27162.5 – 152.23 = 10.27
Step 2: Divide the difference by the actual value
10.27152.23≈0.06746\frac{10.27}{152.23} \approx 0.06746
Step 3: Multiply by 100 to get percentage
0.06746×100=6.746%0.06746 \times 100 = 6.746\%
✅ Correct Answer: D) 6.746%
💡 Explanation (300 words):
Percent error is a way to express how inaccurate a measured value is compared to the actual or accepted value. It helps evaluate the precision of an experimental process. A smaller percent error indicates that the measurement was closer to the true value, meaning higher accuracy.
In this case, the student measured the mass of camphor to be 162.5 grams, while the actual mass was 152.23 grams. The student overestimated the mass. To quantify this overestimation, we calculate the percent error by taking the absolute difference between the measured and actual value, then dividing that by the actual value to see how large the error is relative to the correct value.
Here, the error is 10.27 grams, which is about 6.746% of the actual mass. This means the student’s result was 6.746% higher than the true value.
A percent error of around 6.7% is moderately acceptable depending on the precision required in the experiment. In high-accuracy scientific work, smaller errors (often below 1%) are expected, but in introductory lab settings, an error under 10% is often considered reasonable.
Understanding percent error helps students develop better measurement techniques and identify where improvements can be made in their experimental methods, whether due to instrument calibration, human error, or procedural flaws.