A substance, A2B, has the composition by mass of 60% A and 40% B.What is the composition of AB2 by mass?
(A) 40 % A & 60 %B (B) 50 % A & 50 %B
(C) 27 % A & 73 %B (C) 33 % A & 67 %B
(E) None of these
Chemistry question
2012-04-04 9:35 am
回答 (1)
2012-04-04 2:02 pm
✔ 最佳答案
The answer is : (C) 27 % A & 73 %BLet a be the relative atomic mass of A, and b bethat of B.
In A2B :
Mole ratio A : B
60/a : 40/b = 2 : 1
2(40/b) = 1(60/a)
80a = 60b
a/b = 3/4
Then let a = 3k and b = 4k
In AB2 :
% by mass of A = [3k/(3k + 2*4k)] * 100% = 27%
% by mass of B = [(2*4k)/(3k + 2*4k)] * 100% = 73%
參考: andrew
收錄日期: 2021-04-13 18:36:48
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