Question

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)

Answer 1

Lithium oxide, Li₂O.

Explanation:

Hello!

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

`M_2O+H_2\rightarrow 2M+H_2O`

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:

`5.00gM_2O*(1molM_2O)/((2*X+16)gM_2O)*(2molM)/(1molM_2O)*(XgM)/(1molM)=2.32gM`

Thus, we perform the operations in order to obtain:

`(10X)/((2X+16))=2.32`

So we solve for x as shown below:

`10X=2.32(2X+16)\\\\10X=4.64X+37.12\\\\X=(37.12)/(10-4.64)\\\\X= 6.93g/mol`

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

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