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5\: moles of AB_2  weigh 125\times 10^{-3}kg and 10\: moles of A_2B_2 weigh 300\times 10^{-3}kg. The molar mass of A(M_A) and molar mass of B(M_B) in kg\: mol^{-1} are : 

 

  • Option 1)

    M_A=50\times 10^{-3}\: \: and\: \: M_B=25\times 10^{-3}

  • Option 2)

    M_A=25\times 10^{-3}\: \: and\: \: M_B=50\times 10^{-3}

  • Option 3)

    M_A=5\times 10^{-3}\: \: and\: \: M_B=10\times 10^{-3}

     

  • Option 4)

    M_A=10\times 10^{-3}\: \: and\: \: M_B=5\times 10^{-3}

Answers (1)

best_answer

 

Molar Mass -

The mass of one mole of a substance in grams is called its molar mass.

- wherein

 Molar mass of water = 18 g mol-1

 

 

 

Mole Concept -

One mole is the amount of a substance that contains as many particles or entities as there are atoms in exactly 12 g (or 0.012 kg) of the 12C isotope.

- wherein

one mole = 6.0221367 X 1023   

 

 

 


Let atomic mass of A = x  & atomic mass of B = y

\therefore \: \: \: For\: \: AB_2:

5\left ( x+2y \right )=125g\Rightarrow x+2y=25g\cdots (I)

For\: \: A_2B_2 : 

10\left ( 2x+2y \right )=300g

\Rightarrow x+y=15g\cdots \cdots (II)

Solving equations (I) & (II), simultaneously, we get:

x=5\times 10^{-3}kg     &     y=10\times 10^{-3}kg

Thus, M_A=5\times 10^{-3}kg

          M_B=10\times 10^{-3}kg


Option 1)

M_A=50\times 10^{-3}\: \: and\: \: M_B=25\times 10^{-3}

Option 2)

M_A=25\times 10^{-3}\: \: and\: \: M_B=50\times 10^{-3}

Option 3)

M_A=5\times 10^{-3}\: \: and\: \: M_B=10\times 10^{-3}

 

Option 4)

M_A=10\times 10^{-3}\: \: and\: \: M_B=5\times 10^{-3}

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