One mole of a metallic oxide reacts with one mole of hydrogen to produce two moles of the pure metal and one mole of water. 5.00 g of the metallic oxide produces 2.32 g of the metal. What is the metallic
oxide? (Use molar masses)

Lithium oxide, Li₂O.  

Explanation:

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In this case, according to the given amounts, it is possible to write down the chemical reaction as shown below:

Which means that the metallic oxide has the following formula: M₂O. Next, we can set up the following proportional factors according to the chemical reaction:

Thus, we perform the operations in order to obtain:

So we solve for x as shown below:

Whose molar mass corresponds to lithium, and therefore, the metallic oxide is lithium oxide, Li₂O.  

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