Vanadium forms four different oxides in which the percent by mass of vanadium is respectively 76%, 68%, 61%, and 56%.
Find the formula of the first oxide.
How would I go about doing this? I tried to use my book but there are no examples of this question. Thanks!
76% V so it must be 100-76=24% oxygen since it is vanadium oxide.
So we take 100 g sample which gives us
76 g V and
24 g O
Convert to mols.
moles V = 76/atomic mass V.
moles O = 24/atomic mass O.
Now obtain the ratio of these two so that they are small whole numbers. The easiest way to do that is to divide the smaller number by itself to obtain 1.000, then divide the other one by that same small number.
That should give you the formula.
Post your work if you get stuck.
A2
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.
To find the formula of the first oxide, we need to determine the ratio of vanadium to oxygen in the compound. The percent by mass of vanadium can be used to find the ratio of vanadium to oxygen.
Here's how you can approach this problem step-by-step:
1. Begin by assuming that there is 100 grams of the first oxide.
2. Calculate the mass of vanadium in the compound by multiplying the percent by mass of vanadium (76%) by the assumed mass of the compound (100 grams). This gives us 76 grams of vanadium.
3. Calculate the mass of oxygen in the compound by subtracting the mass of vanadium from the assumed mass of the compound: 100 grams - 76 grams = 24 grams of oxygen.
Now that we have the masses of vanadium and oxygen, we can determine their ratio. Divide the mass of vanadium by the atomic weight of vanadium (50.941 g/mol) and divide the mass of oxygen by the atomic weight of oxygen (16.00 g/mol). This will give us the number of moles of each element.
4. Moles of vanadium = 76 grams / 50.941 g/mol = 1.49 moles of vanadium
5. Moles of oxygen = 24 grams / 16.00 g/mol = 1.50 moles of oxygen
To find the ratio of vanadium to oxygen, divide the number of moles of each element by the smallest number of moles (in this case, vanadium).
6. Divide the moles of vanadium by 1.49: 1.49 moles / 1.49 = 1 mole of vanadium
7. Divide the moles of oxygen by 1.49: 1.50 moles / 1.49 = 1.01 moles of oxygen
Now, we can express the ratio of vanadium to oxygen in terms of whole numbers, by dividing both values by the smallest number (1 mole of vanadium). Since the result is approximately 1 mole for vanadium and 1 mole for oxygen, the ratio is 1:1.
Therefore, the formula of the first oxide of vanadium is V2O5.