What was part a ? there is no way we can answer without backstory .
For pure water the PH level is 7
Your measurement implies that the range of answers is 128.6 mL to 128.8 mL.
If you do not state explicitly the range of uncertainty (e.g., ± 0.5 mL), the <em>implied range of uncertainty</em> is ±1 in the last significant digit.
Thus, a reading of 128.7 mL implies that the volume is 128.7 mL ± 0.1 mL.
I believe the correct answer is the second option. There will be two cobalt atoms in one formula unit of cobalt (III) oxide. It has a chemical formula of Co2O3. This compound is does not naturally occur so it is being synthesized. It is mostly used as bleaching agent.
Density = mass/volume
Therefore,
Density = 60g/30cm
