You determine the correct number of significant figure of a measurement in a graduated cylinder by looking at the smallest division on the graduated cylinder. If the division is divided up to the ones place, you can still read the half of that division or the .50 measurement. So, you can have until the tenths place in your measurement.
Answer:
+4
Explanation:
In PbO2, oxygen exhibits an oxidation number of -2 (since it's not a peroxide or superoxide):
Let the oxidation number of Pb be x. Then, for the compound to be neutral, the oxidation numbers of all atoms should add up to zero.
⇒ x + (−2) + (−2) = 0
x = +4
So the oxidation no. of Pb is +4.
I hope this helps.