Q.2.22 P - Chemistry: Molecular Nature Of Matter And Change

Question

Magnesium oxide (MgO) forms when the metal burns in the air. How many grams of Mg are in534 g of MgO?

 

Step-by-Step Solution

Answer

To calculate the grams of Mg requires calculating the mass ratio of magnesium to magnesium oxide.

The mass ratio of magnesium to magnesium oxide =$\frac{\mathbf{0}\mathbf{.}\mathbf{754}}{\mathbf{1}\mathbf{.}\mathbf{25}}\mathbf{=}\mathbf{0}\mathbf{.}\mathbf{6}$

322.1 g of Mg are in 534 g of  MgO

Step1. Calculation of mass ratio of magnesium to magnesium oxide.

To calculate the grams of Mg requires calculating the mass ratio of magnesium to magnesium oxide.

The mass ratio of magnesium to magnesium oxide=$\frac{\mathbf{0}\mathbf{.}\mathbf{754}}{\mathbf{1}\mathbf{.}\mathbf{25}}\mathbf{=}\mathbf{0}\mathbf{.}\mathbf{6}$

Where according to the question in subpart 1, it had given that for Mg = 0.754 and MgO = 1.25 Therefore final calculation found is 0.6.

Step2. Calculation of grams of Mg in MgO

$\mathbf{5}\mathbf{.}\mathbf{34}\mathit{g}\left(MgO\right)\mathbf{\times }\mathbf{0}\mathbf{.}\mathbf{6}\frac{\mathbf{M}\mathbf{g}}{\mathbf{M}\mathbf{g}\mathbf{O}}\mathbf{=}\mathbf{322}\mathbf{.}\mathbf{1}\mathit{g}$

Hence, 322.1 g of Mg are in 534 g of  MgO