A student cuts six cylinders from a single potato using a cork borer, blots them dry, and weighs each. One cylinder is placed in each of six beakers containing sucrose solutions at 0.0, 0.1, 0.2, 0.3, 0.5, and 1.0 M. After 90 minutes, cylinders are blotted and reweighed. Percent change in mass is calculated for each cylinder.
Why does the student calculate percent change in mass rather than absolute mass change?
- A
Because absolute mass change cannot be calculated
- Bcheck_circle
To control for slight differences in initial cylinder mass
- C
To convert mass into moles of water
- D
Because percent change is the only measurable variable
Explanation
Cylinders are not exactly equal in initial mass. Normalizing to percent change ((final - initial)/initial * 100) makes results comparable across samples and removes systematic bias from cutting variation.