Question

I’m trying to figure out how to do problem number 4

Answer 1

ANSWER

The percentage composition by mass of magnesium in magnesium sulfate is 20.19%

The percentage composition by mass of sulfur is 26.64%

The percentage composition by mass of oxygen is 53.14%

STEP-BY-STEP EXPLANATION:

Firstly, we need to write the chemical formula of magnesium sulfate

The chemical formula of magnesium sulfate is written below as

$\text{MgSO}_4$

The next step is to calculate the molar mass of magnesium sulfate

According to the periodic table, the molar mass of magnesium sulfate is given as 120.366 g/mol

The next step is to find the percentage composition by mass of each of the elements by using the below formula

$\text{ \% composition by mass = }\frac{mass\text{ of the element}}{\text{mass of the compound}}\text{ }\times\text{ 100\%}$

Recall that, the molar mass of magnesium is 24.305g/mol, the molar mass of sulfur is 32.065g/mol, and the molar mass of oxygen is 15.99g/mol

For magnesium

$\begin{gathered} \text{ \%composition by mass of magnesium = }\frac{24.305}{120.366}\times\text{ 100\%} \\ \text{ \% compositin by mass of magnesium= }0.2019\text{ }\times\text{ 100\%} \\ \text{ \% composition by mass of magnesium = 20.19\%} \end{gathered}$

Therefore, the percentage composition by mass of magnesium in magnesium sulfate is 20.19%

For Sulfur

$\begin{gathered} \text{ \% composition by mass of sulfur = }\frac{32.065}{120.366}\times\text{ 100\%} \\ \text{ \% composition by mass of sulfur = 0.266 }\times\text{ 100\%} \\ \text{ \% composition by mass of sulfur = 26.64\%} \end{gathered}$

Therefore, the percentage composition by mass of sulfur is 26.64%

for Oxygen

$\begin{gathered} \text{ \% composition by mass of oxygen = }\frac{(15.99)\text{ }\times\text{ 4}}{120.366}\times\text{ 100\%} \\ \text{ \% composition by mass of oxygen = }\frac{63.69}{120.366}\times\text{ 100\%} \\ \text{ \% composition by mass of oxygen = 0.5314 }\times100\text{ \%} \\ \text{ \% composition by mass of oxygen = 53.14\%} \end{gathered}$

Therefore, the percentage composition by mass of oxygen is 53.14%