Question

Lập CTHH của các hợp chất sau, biết:

a) Mg=25.26% ; Cl=74.74%

b) Al=52.9% ; O=47.1%

c) Al= 15.79% ; S= 28.07% ; O=56.14%

d) Mg= 60% ; O= 40%

Answer 1

a) Gọi CTHH là Mg_xCl_y

Ta có: \(24x\div35,5y=25,26\div74,74\)

\(\Rightarrow x\div y=\frac{25,26}{24}\div\frac{74,74}{35,5}\)

\(\Rightarrow x\div y=1,0525\div2,1054\)

\(\Rightarrow x\div y=1\div2\)

Vậy CTHH là MgCl₂

b) Gọi CTHH là Al_xO_y

Ta có: \(27x\div16y=52,9\div47,1\)

\(\Rightarrow x\div y=\frac{52,9}{27}\div\frac{47,1}{16}\)

\(\Rightarrow x\div y=1,95926\div2,94375\)

\(\Rightarrow x\div y=1\div1,5\)

\(\Rightarrow x\div y=2\div3\)

Vậy CTHH là Al₂O₃

c) Gọi CTHH là Al_xS_yO_z

Ta có: \(27x\div32y\div16z=15,79\div28,07\div56,14\)

\(\Rightarrow x\div y\div z=\frac{15,79}{27}\div\frac{28,07}{32}\div\frac{56,14}{16}\)

\(\Rightarrow x\div y\div z=0,585\div0,877\div3,508\)

\(\Rightarrow x\div y\div z=1\div1,5\div6\)

\(\Rightarrow x\div y\div z=2\div3\div12\)

Vậy CTHH là Al₂S₃O₁₂ hay Al₂(SO₄)₃

d) Gọi CTHH là Mg_xO_y

Ta có: \(24x\div16y=60\div40\)

\(\Rightarrow x\div y=\frac{60}{24}\div\frac{40}{16}\)

\(\Rightarrow x\div y=1\div1\)

Vậy CTHH là MgO

Answer 2

Ờ nhìn lại câu c thấy nhầm :)

\(x:y:z=\frac{15,79}{27}:\frac{28,07}{32}:\frac{56,14}{16}\Leftrightarrow x:y:z=2:3:12\\ \rightarrow CTHH:Al_2\left(SO_4\right)_3\)

Answer 3

a) Gọi CTHH của hợp chất là Mg_xCl_y

Ta có: x:y = \(\frac{25,26}{24}:\frac{74,74}{35,5}\) = 1:2

=> x = 1 ; y = 2

CTHH: MgCl₂

b) Gọi CTHH là Al_xO_y

Ta có: x:y = \(\frac{52,9}{27}:\frac{47,1}{16}\) = 2:3

=> x = 2; y = 3

Vậy: CTHH là Al₂O₃

c) Gọi CTHH là Al_xS_yO_z

Ta có: x:y :z= \(\frac{15,7}{27}:\frac{28,07}{32}:\frac{47,1}{16}\) = 2:3:12

Vậy: CTHH là Al₂S₃O₁₂

hay Al₂(SO₄)₃

d)Gọi CTHH là Mg_xO_y

Ta có: x:y = \(\frac{60}{24}:\frac{40}{16}\) = 1:1

Vậy: CTHH là MgO

Answer 4

\(a.CTPT:Mg_xCl_y\\ \Rightarrow\frac{24x}{35,5y}=\frac{25,26}{74,74}\Leftrightarrow\frac{x}{y}=\frac{1}{2}\\ \rightarrow CTHH:MgCl_2\\ b.CTPT:Al_xO_y\\ \Rightarrow\frac{27x}{16y}=\frac{52,9}{47,1}\Leftrightarrow\frac{x}{y}=\frac{2}{3}\\ \rightarrow CTHH:Al_2O_3\\ c.CTPT:Al_xS_yO_z\\ \Rightarrow x:y:z=\frac{27}{15,79}:\frac{32}{28,07}:\frac{16}{56,14}\Leftrightarrow x:y:z=3:2:8\\ \rightarrow CTHH:Al_3\left(SO_4\right)_2???\\ d.CTPT:Mg_xO_y\\ \Rightarrow\frac{24x}{16y}=\frac{60}{40}\Leftrightarrow\frac{x}{y}=\frac{1}{1}\\ \rightarrow CTHH:MgO\)