Cho chất a gồm fe và oxi.Biết oxi chiếm 30%khối lượng.Tìm công thức hoá học của a

1 answer:

3 0

Gọi: số nguyên tử của Fe là x.
=> Nguyên tử khối của Fe là: 56x.
Gọi: số nguyên tử của O là y.
=> Nguyên tử khối của O là: 16x
Ta có:
16x/160=30%
⇔16x=48
⇒x=3
56y/160=70%
⇒56y=112
⇒y=2
Vậy: Fe có 3 nguyên tử và O có 2 nguyên tử trong hc trên.
CTHH: Fe2O3

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