Aluminium and oxygen react to produce aluminium oxide, 4 Al + 3 02 - 2 AL, O
How many kilograms of aluminium oxide are formed when 5,4 kg of aluminium react
with excess oxygen?
A 5,4 kg
B 88 kg
C 10.2 kg
D 33,6 kg

The balanced reaction is

4 Al + 3 O₂   →   2 Al₂O₃

so that for every 4 moles of Al and 3 moles of O2, you end up with 2 moles of Al₂O₃.

• Al has molar mass ≈ 26.982 g/mol

• O has molar mass ≈ 15.999 g/mol

• Al₂O₃ thus has molar mass ≈ 101.961 g/mol

You start with 5.4 kg = 5,400 g of Al, or

(5.4 kg Al) • (1/26.982 mol/g) ≈ 200.133 mol Al

Al₂O₃ is produced in a ratio of 2 moles to every 4 moles of Al, so you end up with about 100.067 mol Al₂O₃, which has a mass of

(100.067 mol Al₂O₃) • (101.961 g/mol) ≈ 10,202 g = 10.2 kg

so the answer is C.

vanderwaal's forces of attraction are the electrostatic intermolecular forces that exist in a molecule due to the temporary or permanent dipoles that are developed in a molecule. in , the major intermolecular forces are dipole-dipole interactions as the molecule is polar (bent structure). so the vanderwaal's forces of interaction in between molecules are the permanent dipole-dipole interactions that develop due to the dipole that exists in between the polar h - s bond. the positively charged hydrogen atom is attracted towards the negative end of the dipole that is sulfur of the adjacent molecule. therefore, these forces of attraction are relatively stronger than that of london dispersion forces that exist in non polar molecules.