Question

question 1 what is the percent by mass of aluminum in aluminum sulfate, al2(so4)3? (molar mass of al2(so4)3 = 342.14 g/mol) o 35.94 % o 7.886 % o 45.70 % o 15.77 % o 21.93 %

Explanation:

Step1: Determine the molar mass of aluminum in the compound

Aluminum has an atomic - mass of approximately 26.98 g/mol. In \(Al_2(SO_4)_3\), there are 2 moles of Al. So the total mass of Al in one mole of \(Al_2(SO_4)_3\) is \(2\times26.98\ g = 53.96\ g\).

Step2: Calculate the percent - by - mass of Al

The formula for percent - by - mass is \(\text{Percent by mass}=\frac{\text{Mass of element}}{\text{Molar mass of compound}}\times100\%\). The molar mass of \(Al_2(SO_4)_3\) is given as 342.14 g/mol. So \(\text{Percent by mass of Al}=\frac{53.96\ g}{342.14\ g}\times 100\%\approx15.77\%\)

Answer:

15.77%