Well, finding the formula of an oxide can be quite challenging, but don't worry, I'm here to help you with a smile!
Since you have the percent by mass of vanadium in each oxide, we can assume that the oxygen also contributes to the remaining percent by mass in each oxide.
Let's start with the first oxide, which has vanadium accounting for 76% of the mass.
To determine the formula, we need to assume a certain total mass for the oxide. Let's assume we have 100 grams of the first oxide.
If vanadium accounts for 76% of the mass, then oxygen must account for the remaining 24%.
So, in 100 grams, we have 76 grams of vanadium and 24 grams of oxygen.
Now we can find the ratio of the number of moles of vanadium to oxygen.
The molar mass of vanadium is 50.94 g/mol, and the molar mass of oxygen is approximately 16.00 g/mol.
Dividing the grams by the molar mass gives us the number of moles.
For vanadium: 76 grams / 50.94 g/mol ≈ 1.49 moles
For oxygen: 24 grams / 16.00 g/mol ≈ 1.50 moles
Since the ratio of moles is close to 1:1, we can assume the empirical formula is VO. Therefore, the formula of the first oxide is VO.
Remember, this is just a possible formula based on assumptions. To have a more definitive answer, additional information or experiments might be required.