Two elements A and B form compounds having molecular formula AB2 and AB4 when dissolved in 20 gram of benzene, one gram of AB2 lowers the freezing point by2.3 Kelvin whereas 1.0 gram of AB4 lowers it by 1.3 Kelvin. calculate the atomic mass of A and B.
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Answers
Answered by
3
A+2B = 110.87
A+4B = 196.15
solving we get A = 42.64
B= 25.59
(cryscopic constant is considered 5.1 )
A+4B = 196.15
solving we get A = 42.64
B= 25.59
(cryscopic constant is considered 5.1 )
ans is right??
bcoz I found problem in value of kf and u solve it
welcome
but u don't solve it full
no problem I'll manage
yeah
won't you have the formula,?
no I have that's why I'm saying I'll manage
ok
t = k×(w × 1000)/(w'×m) : k is kf . w is mass of solute. w' is mass of solvent . m is molecular weight of solute. I think it will help you. ok bye.
Answered by
1
Answer:
the atomic mass of a is 25.59 g/mol and b is 42.64 g/mol
Explanation:
As we know that,
MB=(kf×WB×1000)/(WA×deltaTf)
Now deltaTf =2.3, WB=1.0, WA=20,KF=5.1( given)
putting tye values in the equation.
MB=(5.1×1×1000)/(20×2.3)
=110.87 g/mol
Therefore Mab2=110.9
for AB4 compound
delta Tf=1.3,WB=1,Wa=20
MB=(5.1×1×1000)/(20×1.3)
=196g/mol
therefore MAB=196
Let x be the atomic masw of Aand y be the atomic mass of B
Then MAB2=x+2y=110.9______(1)
&MAB=x+4y=196________(2)
subtracting (2)from(1)
we get,
2y=196-110.9
y=85.1/2
y= 42.6
putting tye value of y in (1)
we get,
x=110.9 -2×42.6
x=25.59
Therefore, Atomic mass of A=25.59U and Atomic mass of B =42.6U.
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