Answer:
2.086 moles of Al(Cn)₃ are in 217g of the compound
Step-by-step explanation:
To know the amount of moles of Al(CN)₃ in 217 g of the compound, you must know the molar mass of the compound. For that, you must know the atomic mass of each element that forms the compound and its relative abundance.
The atomic mass of each compound is obtained from the periodic table of the elements:
- Al: 27 g/mol
- C: 12 g/mol
- N: 14 g/mol
Considering relative abundance of each element in the compound, the molar mass is:
Al(CN)₃= 27 g/mol + 3*( 12 g/mol + 14 g/mol)= 105 g/mol
Now you apply a rule of three as follows: if 105 g are present in 1 mol of the compound, 217 g are present in how many moles of Al(CN)₃?

moles= 2.086
2.086 moles of Al(Cn)₃ are in 217g of the compound