Question

How many moles of aluminum oxide (Al2O3) are in a sample with a mass of 204.0 g?

A) 1.000 moles
B) 2.000 moles
C) 3.000 moles
D) 4.000 moles

Answer 1

To find the number of moles of aluminum oxide (Al2O3) in a sample with a mass of 204.0 g, divide the mass by the molar mass of Al2O3, which is 101.96 g/mol. The answer is 2.000 moles.

Step-by-step explanation:

To determine the number of moles of aluminum oxide (Al2O3) in a sample with a mass of 204.0 g, we need to use the molar mass of Al2O3. The molar mass of Al2O3 is calculated by adding the atomic masses of aluminum (Al) and oxygen (O) in the compound.

The atomic mass of Al is 26.98 g/mol and the atomic mass of O is 16.00 g/mol.

Therefore, the molar mass of Al2O3 is (2 * 26.98 g/mol) + (3 * 16.00 g/mol) = 101.96 g/mol.

To calculate the number of moles, we divide the mass of the sample by the molar mass:

Number of moles = 204.0 g / 101.96 g/mol = 2.000 moles.

So, the correct answer is B) 2.000 moles.