Magnesium oxide decomposes into magnesium and oxygen. If 8.06 g of magnesium oxide decomposes to form 4.86 g of magnesium, what mass of oxygen gas is also released in the reaction?

31.84g of O2

Explanation:

1) write the balanced chemical equation

2MgO> 2Mg + O2

2) convert the given mass of MgO into moles by dividing the given mass with molar mass = 8.06/40.3044g/mol

= 0.199moles

3) According to the balanced equation if 2 moles of magnesium oxide produces 1 mole of oxygen then 0.199moles of magnesium oxide produces 0.199/2= 0.0995moles of O2

4) convert these moles to mass by multiplying with the molar mass of O2 = 0.995×32g/mol

= 31.83801g

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