Final answer:
Percent error is calculated by subtracting the accepted value from the experimental value, taking the absolute value of the result, dividing by the accepted value, and then multiplying by 100% to express it as a percentage.
Step-by-step explanation:
To calculate percent error, you first need to determine the error by subtracting the accepted value from the experimental value. Next, take the absolute value of this error to avoid any negative result, which can be confusing when discussing errors. The formula for percent error is:
Percent Error = | (experimental value - accepted value) / accepted value | × 100%
For example, for an aluminum density measurement, if the experimental value is 2.45 g/cm³ and the accepted value is 2.70 g/cm³, the error is 2.45 - 2.70 = -0.25. Taking the absolute value, we get 0.25. Dividing by the accepted value (0.25 / 2.70) and then multiplying by 100% gives us the percent error, which in this case would be approximately 9.26%.