The weight of the purified caffeine is often much lower than the weight of the crude caffeine. Explain why the percent recovery is frequently low?

see explanation

Explanation:

When caffeine is purified, the impurities are removed,  these impurities are responsible for the greater mass of pure caffeine compared to the mass of the pure sample.

The percent recovery of caffeine is frequently low because some caffeine is often left behind in the solvent during the process of recrystallization.

Secondly, since caffeine is a sublime substance, some caffeine may be lost o sublimation leading to a low percent recovery of pure caffeine.

8 m/s because for him to get the same amount of energy as ray is putting out, bobby, who weighs half as much as ray, needs to run twice as fast.

because of all the things that happen around the us, many people get into arguments which sadly could get physical, but we should actually make a change for that.