Question

How can I calculate the percent composition of magnesium oxide with Masses of Magnesium and Oxygen? After that how do I find percent error.

Answer 1

In the given question firstly we have to define the exact Percentage weight are. Now after that we can use this information and do the step by step work of finding the Percentage weight through the formula of $\% = \dfrac{{{\text{weight of element}}}}{{{\text{total weight of compound}}}}$ .

Complete step by step answer:
The given question statement asks about the entire process through which we would be able to get the proper and correct Percentage weight. So we have to explain what exactly Magnesium oxide is. Now by this we get the steps and use it to get the answer.
Magnesium oxide is the compound that has chemical formula MgO, that will mean that in every sample of this substance there is the same number of Oxygen and Magnesium atoms.
Now when we notice from the modern day periodic table we get that the atomic masses are 24.3 (Mg) and 16.0 (O). Magnesium atoms are heavier than oxygen atoms, so we expect more than 50% of magnesium in the weight composition.
Now for the calculation of the total mass of the MgO we get by taking just one atom of Mg and one atom of O you will get a mass of $16.0{\text{ }} + {\text{ }}24.3{\text{ }} = {\text{ }}40.3$ . Which would be for the unit that represents the minimum amount of magnesium oxide.
So we know that the mass of oxygen in the compound is $16g$ .
Now the percentage would be $\dfrac{{16.0}}{{40.3}} \times 100{\text{ }} = {\text{ }}39.7\%$ in mass of oxygen
So we know that the mass of magnesium in the compound is $24.3g$
Now the percentage would be $\dfrac{{24.3}}{{40.3}} \times 100{\text{ }} = {\text{ 60}}{\text{.3}}\%$

Note: MgO is prized as a refractory material, i.e. a solid that is physically and chemically stable at high temperatures. It has two useful attributes: high thermal conductivity and low electrical conductivity. Filling the spiral Calrod range top heating elements on kitchen electric stoves is a major use.