Question

X and y are two elements which form x2y3 and x3y4. if 0.20 mol of x2y3 weighs 32.0 g and 0.4 mol of x3y4 weighs 92.8 g, the atomic masses of x and y are, respectively

Answer 1

Molecular weight of X2Y3=32.0g/0.2mol

X2Y3=32.0g/0.2mol=160g/mol

Molecular weight of X^3Y4=92.8g/0.4mol

X3Y4=92.8g/0.4mol=232g/mol

Now suppose the atomic weight of X=a and atomic weight of Y=b

Then 2a+3b=160 and 3a+4b=232(i)

a=(160-3b)/2(ii)

Put value of (ii) in (i)

3((160-3b)/2)+4b=232

After solving

a=56 and b=16