# Stociometry problem

1. Aug 30, 2007

### Benzoate

1. The problem statement, all variables and given/known data

What is the atomic mass of element X if 6.08 g XCl3 contains 1.37 g of X

2. Relevant equations

3. The attempt at a solution

(6.08 g XCl^3)*(1 mol X/107.729 g *XCl3)*(1.37 g X/1 mol X)=.077 g of X

That can't be right , because 1.37 g of X can't be included in the molar mass of XCl3

2. Aug 30, 2007

### symbolipoint

Long time since passed since doing stoichiometry exercises...

Total XCl3 was 6.08, since grams X was 1.37, amount of Cl mass was 4.71 grams.

How many formula units Cl ? 4.71/(35.5);
Ratio of X formula units to Cl formula units = 1/3

How many moles of X ? ((4.71)/(35.5))*(1/3)

Now you have calculated moles of X or formula units of X, and were given grams of X.
Finish the calculation.

3. Aug 31, 2007

### Gokul43201

Staff Emeritus
Roco, your answer was correct, but we can't go about handing out complete solutions to homework questions.

Benzoate, to simplify symbolipt's method a wee bit...

Answer this question: If there's 4.71 gms of Cl3 and 1.37 gms of X (in a sample of XCl3), what is the formula mass of X?

4. Aug 31, 2007

### rocomath

sorry! will comply.