0.02 moles of a certain aluminum compound has a mass of 1.56 g. This compound may be ________.

Question

Quizplus · Accepted Answer

To calculate the molar mass of the compound, we can use the formula:

molar mass = mass / amount of substance

Substituting the given values, we get:

molar mass = 1.56 g / 0.02 mol = 78 g/mol

Looking at the possible compounds, we can calculate their molar masses and compare them to the calculated value:

A) aluminum hydroxide: Al(OH)3
molar mass = 27 + 3(16 + 1) = 78 g/mol

B) aluminum nitrate: Al(NO3)3
molar mass = 27 + 3(14 + 48) = 213 g/mol

C) aluminum cyanide: Al(CN)3
molar mass = 27 + 3(12 + 14) = 105 g/mol

D) aluminum permanganate: Al(MnO4)3
molar mass = 27 + 3(55 + 4(16)) = 606 g/mol

Since only aluminum hydroxide has a molar mass of 78 g/mol, it is the best choice.

002 Moles of a Certain Aluminum Compound Has a Mass