Question

The atomic mass of a hypothetical element X is 33.42 amu. A 27.22 g sample of X combines with 84.10 g of another hypothetical element Y to form the compound XY. The atomic mass of Y is:

• A. 68.50 amu
• B. 69.84 amu
• C. 103.3 amu
• D. 111.3 amu

Answer 1

The correct option is C 103.3 amu

We have,

$X+Y\to XY$

so, moles of X = moles of Y

$\frac{27.22}{33.42}=\frac{84.1}{M}$

where M is the atomic mass of Y

So, we get, M = 103.25

So, the atomic mass of Y = 103.3 amu