Final answer:
The student's percent error in the density measurement of aluminum is calculated as |(2.85 - 2.70) / 2.70| × 100%, which equals 5.56%.
Step-by-step explanation:
The student's percent error in determining the density of a piece of pure aluminum can be calculated using the formula:
Error = (experimental value - accepted value) / accepted value × 100%.
The experimental value is 2.85 g/cm³, and the accepted value is 2.70 g/cm³. Plugging these values into the formula gives:
Error = |(2.85 - 2.70) / 2.70| × 100%
Error = |0.15 / 2.70| × 100%
Error = 0.0556 × 100%
Error = 5.56%
This means the student's percent error in measuring the density of aluminum is 5.56%.