Question

vanadium forms dour different oxides. the mass percentage of vanadium in the pure oxides are measured as being 76.10%, 67.98%, 61.42% and 56.02%.

calculate the mole fraction and mass percentage of vanadium in a mixture containing 4.00kg of the first given oxide at 76.10%

Answer 1

Vanadium has a molar mass of 51 g/gmol

Oxygen has a molar mass of 16 g/gmol

Mass % vanadium is 76.1

mass % of oxygen is 100 - 76.1 = 23.9

moles of vanadium = mass / molar mass = 76.1 / 51= 1.49

moles of oxygen = mass / molar mass = 23.9 / 16 = 1.49

If we divide this values by the lower number (1.49 for this case) you would get 1 for V and 1 for O so the oxide is

VO

For the mole fraction of vanadium, looking at the compound VO, we can see that you need for 1 mole of Vanadium Oxide 1 mole of Vanadium and 1 mole of O so the mole fraction is 0.5 for V and 0.5 for O

since we are talking about percentages and mole fraction we dont need to do calculations because the percentages will remain the same