Question

A piece of magnesium ribbion reacts with oxygen to form magnesium oxide , MgO . What is the percent composition of the compound

Answer 1

see explanation below

Step-by-step explanation:

In this case, we have the following reaction:

Mg + 1/2O₂ -------> MgO

Now, according to this reaction we want to know the percent composition of MgO. The problem is not providing the mass of the initial reactants and the product, so we can use the atomic weights of the components, to do this

The molecular weight of Mg is 24.305 g/mol, and O is 15.999 g/mol, so, let's calculate the molar mass of MgO:

MM MgO = 24.305 + 15.999 = 40.304 g/mol

Now with this weight, let's see the percent composition of this compound:

%Mg = 24.305 / 40.304 * 100 = 60.304 %

%O = 15.999 / 40.304 * 100 = 39.696 %

And this would be the percent composition of MgO