Two elements A and B form the compounds A B2 and A B3. If 0.25 mole of A B2 weighs 16 g and 0.25 mole of A B3 weighs 20 , then the atomic masses of A and B are respectively

Question

Two elements A and B form the compounds A B2 and A B3. If 0.25 mole of A B2 weighs 16 g and 0.25 mole of A B3 weighs 20 , then the atomic masses of A and B are respectively (A) 16, 32 (B) 16, 24 (C) 32, 16 (D) 16, 21

Tardigrade Admin · Accepted Answer

Molecular weight of A B2=(16/0.25)=64 Molecular weight of A B3=(20/0.25)=80 Let atomic weight of A and B be x and y respectively. Then, x+2 y=64 x+3 y=80 or x=32, y=16

Q. Two elements $A$ and $B$ form the compounds $A B_{2}$ and $A B_{3}$ . If $0.25 m o l e$ of $A B_{2}$ weighs $16 g$ and $0.25$ mole of $A B_{3}$ weighs $20$ , then the atomic masses of $A$ and $B$ are respectively

16, 32

16, 24

32, 16

16, 21

Molecular weight of $A B_{2} = \frac{16}{0.25} = 64$

Molecular weight of $A B_{3} = \frac{20}{0.25} = 80$

Let atomic weight of $A$ and $B$ be $x$ and $y$ respectively.

Then, $x + 2 y = 64$

$x + 3 y = 80$

or $x = 32, y = 16$

Q. Two elements A and B form the compounds AB2​ and AB3​. If 0.25mole of AB2​ weighs 16g and 0.25 mole of AB3​ weighs 20 , then the atomic masses of A and B are respectively