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- a student has 872g if Pb. how many moles of Pb is this?

The answer is 4,2 moles.

Explanation:

n(Pb) = m(Pb) / Ar(Pb, you can see it in periodic table of elements)

= 872 g / 207,2 g moles⁻¹

= 4,2 moles

2b2t

explanation:

2b2t

answer:

the answer is 6 valence electrons.

explanation:

valence is the # of electrons on the outer most shell of an atom.

oxygen has 6.

although, the valency of oxygen is 2, because it only needs to make 2 covalent bonds, or gain 2 electrons, to achieve the stable octet configuration of a noble gas.

that's it!

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~ trueboss72