An element M forms a chloride which contains 34,66 % M.
Which of the following is true?
(A)The element is Aluminum
(B)The molecular formula of the compound is MCl
(C)if the chloride is reacted with NaOH a green precipitate is formed.
(D)the metal has amphoteric properties
(E)the metal M can also form another chloride MCl2.
Note: You are not allowed to use a calculator during the SAT exam. Try not to use one.Good luck.
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7 comments:
i tried doing some math, and i dont think its a or e. and maybe its not d. so im guessing c.
I think it is e, probably FeCl3 (cannot be sure without calculator)
shouldnt it be 34.66% instead of '34,77%'
The answer is E, the cation is Fe (III);
I wrote 34,66 not 34,77 and this is what i see; However you can express it a little bit differently depending on the values that you take for the atomic masses.
can u explain how its e though ?
You consider the formula of the chloride MClx, where x is the valence of the metal.
The percent of metal is
Am/[Am+x*35.5]=0.3466
where Am is the atomic mass of the metal.
You obtain Am = 18.8 * x
By replacing x with different integers you obtain the following results:
x=1, Am= 18.8
x=2, Am=37.7
x=3, Am=56,4
By looking into a periodical table for the atomic masses you obtain that only for x is 3 the solution is viable; therefore the metal is the iron.
I did it a little differently...just subtract 100 from the 34.66...65 something, (this is the percent of Cl) and then just compare that to your M percentage...1:2 ratio...
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