Question

Scientists discover two new elements, element A and element X, and are able to determine their atomic mass.

Element A has an atomic mass of 17 amu

Element X has an atomic mass of 76 amu.

These elements combine to form a compound with the following formula: A2X3. Determine the molar mass of this compound.

Answer 1

Since element A has an atomic mass of 17 amu, the total mass of the 2 A atoms in the molecule = 2 * 17 amu = 34 amu.
Similarly the total mass of the 3 X atoms is = 3 * 76 amu = 228 amu.
Therefore the total molar mass of the compound = 262 g/mol.