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.
Baking soda is sodium bicarbonate in anhydrous form without any water of crystallisation and it is widely used as dry fire extinguisher because of its alkali nature.
Explanation:
The scientific notation:
where
and k is integer.
We have the example:
You can write the numbers in a "normal" form:
Make the sum:
And next write it in the scientific notation:
<h3>Other method:</h3>
You can add numbers in scientific notation if the power of tens in both number is the same.
Therefore you must convert the first number:
Now, you can make the sum:
