Answer:
(a) for a 25 mL pipet, usually the uncertainly is ± 0,1 mL, or ± 0,05 mL. So the significant number should be at less 1.
(b) for a centigram balance, we don't need to add the significant numbers, because the unit of mass received here is in mg.
(c) the same for the last case, we don't add any significant numbers because the volume and mass obtained in uncertain.
Explanation:
