In the 19th century, relative atomic masses (RAMs) were determined by gravimetric analysis - VCE - SSCE Chemistry - Question 4 - 2004 - Paper 1

The molar mass of oxygen (O) is approximately 16 g/mol. We can calculate the number of moles of oxygen that reacted:

Moles of oxygen = ( \frac{\text{mass}}{\text{molar mass}} = \frac{0.80 \text{ g}}{16 \text{ g/mol}} = 0.05 \text{ mol} )

From the oxide formula XO, we know that one mole of X reacts with one mole of oxygen. Hence, the moles of X are also 0.05 mol.

The relative atomic mass (RAM) of element X can be calculated using the mass of X and the number of moles:

RAM of X = ( \frac{\text{mass}}{\text{moles}} = \frac{3.27 \text{ g}}{0.05 \text{ mol}} = 65.4 \text{ g/mol} )

Thus, the RAM of X is 65.4 g/mol.

From the options given, the RAM of X is C. 65.4.