An element x forms an iodide (xi3) and a chloride (xcl3). the iodide is quantitatively converted to the chloride when it is heated in a stream of chlorine: 2xi3+3cl2â2xcl3+3i2 if 0.5500 g of xi3 is treated, 0.2596 g of xcl3 is obtained. part a calculate the atomic weight of the element x.

The balanced chemical reaction is written as:

2XI3 + 3Cl2 ---> 2XCl3 + 3I2 
To determine the atomic weight of element X, we need to know make a relation between the mass of the reactant XI3 and the mass of the product XCl3. In this case, we write equations that would equate to the mole of X in that particular substance. We do as follows:

0.5500 g XI3 ( 1 mol / x + 380.7 g XI3 ) ( 1 mol X / 1 mol XI3 ) = 0.2596 g XCl3 ( 1 mol / x + 106.35 g XCl3 ) ( 1 mol X / 1 mol XCl3 )

where x is the atomic weight of element X.

Simplifying the equation,

0.5500/ (x+380.7) = 0.2596 / (x+ 106.35)

Solving for x,
x = 138.90 g/ mol