Question

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

Answer 1

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%

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{ }*\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 = }(24.305)/(120.366)*\text{ 100\%} \\ \text{ \% compositin by mass of magnesium= }0.2019\text{ }*\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 = }(32.065)/(120.366)*\text{ 100\%} \\ \text{ \% composition by mass of sulfur = 0.266 }*\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{ }*\text{ 4}}{120.366}*\text{ 100\%} \\ \text{ \% composition by mass of oxygen = }(63.69)/(120.366)*\text{ 100\%} \\ \text{ \% composition by mass of oxygen = 0.5314 }*100\text{ \%} \\ \text{ \% composition by mass of oxygen = 53.14\%} \end{gathered}`

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