# Question #86b83

##### 1 Answer

Mar 21, 2017

#### Answer:

Element X is vanadium. Here's how we know...

#### Explanation:

Start by assuming we have 100 g of this compound. That way, the percentages translate directly into masses: 44 g of O and 56 g of X.

Now, calculate the moles of oxygen:

Now, since the formula is

Since there is actually 2.75 moles of O, there must be #2.75 xx 2/5 = 1.1 moles of X.

Since 1.1 mole of X has a mass of 56 g, the molar mass of X must be

or

Looking at the periodic table, we see it must be vanadium.