Answer:
Crisscross method is simply writing the charges crossly near each element. Since oxidation number of Mg (metal) is +2 and oxygen (nonmetal) is -2, if we cross them and write next to each; we get Mg2O2 .

<em>What quantity of energy is released when 506 g of liquid water freezes?</em>
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= 169 kJ
Answer:
C) 5 moles of Argon (Ar)
Explanation:
5mol Na x 22.990g Na/ 1 mol Na = 114.95g Na
5mol P x 30.974g P/ 1 mol P = 154.87g P
5mol Ar x 39.948g Ar/ 1 mol Ar = 199.74g Ar
Therefore Ar has the greatesr mass.