Question

When magnesium oxidizes it utilizes 48 g of magnesium for every 32 g of diatomic oxygen to produce magnesium oxide. See below for questions?
Write the word equation.
Write the chemical equation.
Determine the chemical formula of magnesium oxide. Be sure to show your work with 'criss-cross'.
Balance the chemical equation.
Mathematically show how the atoms in the balanced equation prove the Law of Conservation of Matter.
Use the atomic masses of O and Mg to prove that the masses of Mg (48g) and O (32g) in the reaction/equation uphold the Law of conservation of Matter (mass)
Determine the mass of magnesium oxide produced.

Answer 1

In magnesium oxide, there is one atom of magnesium and one atom of oxygen. For finding the conservation of mass, then we have to find the total mass in the reactant and total mass in the product, if the mass is the same then the law of conservation mass is followed.

Complete answer:
The word equation will be:
Magnesium plus dioxygen will give Magnesium oxide
The chemical equation will be:
$Mg+{{O}_{2}}\to MgO$
The formula of magnesium oxide is MgO. In the ionic form it will be:
$M{{g}^{2+}}+{{O}^{2-}}$
When we criss-cross, the formula will be $M{{g}_{2}}{{O}_{2}}$. As the subscript is the same and can be divided by two so the formula becomes MgO.
The balanced equation will be:
$2Mg+{{O}_{2}}\to 2MgO$
Since the balanced equation is:
$2Mg+{{O}_{2}}\to 2MgO$
On the reactant side, there are two magnesium atoms and two oxygen atoms. On the product side, there are two magnesium and oxygen atoms. So, the matter is conserved.
By finding the total mass on the reactant side and total mass on the product side, we can uphold the law of conservation of matter.
On reactant side,
2 x Mg = 2 x 24 = 48 grams
2 x O = 2 x 16 = 32 grams
48 + 32 = 80 grams
On product side,
Mass of MgO is 40 g/mol
2 x MgO = 2 x 40 = 80 grams
So, the mass is the same on both the side, the law of conservation of mass is true for the equation.
To determine the mass of MgO produced.
We know the molar mass of:
Mg = 24 g/mol
${{O}_{2}}$ = 32 g/mol
MgO = 40 g/mol
$\dfrac{48}{24}\text{ x }\dfrac{32}{32}\text{ = }\dfrac{x}{40}$
$x=80\text{ g}$
So, the mass of MgO produced is 80 g.

Note:
If the compound is in the diatomic form then its molar mass will also double. For example, the atomic mass of oxygen is 16, but when the oxygen is present in the diatomic form then its molar mass will be 32.