<span>
Sodium Oxide= Na2O
The formula mass of Na2O is (2x23) + 16 = 62g/mol
% Na= (46/62) x 100 = 74%
% O= (16/62) x 100 = 26%</span><span>
</span>
one substance becomes two new substances
Li
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There are 115 known elements as of today (Feb. 13, 2016)
so, 'C' is the correct answer
