To find the final mass of the sugar crystals, we need to subtract the change in mass from the initial mass.
Initial mass of sugar crystals = 22 grams
Change in mass = -6 grams
Final mass = Initial mass + Change in mass
Final mass = 22 grams + (-6 grams)
Final mass = 22 grams - 6 grams
Final mass = 16 grams
Therefore, the final mass of the sugar crystals is 16 grams.