Question

A and B are two elements. These react to form compound A2B3 and AB2. If 0.15 moles of each of A2B3 and AB2 weigh 15.9 g and 9.3 g respectively Calculate the atomic mass of A and B.

Answer 1

Answer:

A= 26 g

B= 18g

Explanation:

moles = given mass / molecular mass

Answer 2

The correct answer is x = 36u and y = 18u.

Given: Moles of $A_{2} B_{3}$ = 0.15

Moles of $A_{} B_{2}$ = 0.15

Weight of $A_{2} B_{3}$ = 15.9g.

Weight of $A_{} B_{2}$ = 9.3g.

To Find: Atomic mass of A and B.

Solution:

Let molar mass of A = x.

Let molar mass of B = y.

Mass of $A_{2} B_{3}$ = 2x + 3y.

Mass of $A_{} B_{2}$ = x + 2y.

Number of moles = $\frac{Given mass}{Molar mass}$

Equation for $A_{2} B_{3}$

$0.15=\frac{15.9}{2x+3y}$

2x + 3y = 106

Equation of $A_{} B_{2}$

$0.15=\frac{9.3}{x+2y}$

x + 2y = 62

Solving both the equations

x = 18$g mole^{-1}$ and y = 26 $g mole^{-1}$.

Hence the final answer is x = 36u and y = 18u.

#SPJ3