a) \(K^I_x\left(CO_3\right)^{II}_y\)

Theo quy tắc hóa trị: x.I = y.II

=> \(\dfrac{x}{y}=\dfrac{II}{I}=\dfrac{2}{1}\)

=> K₂CO₃

b) \(Fe^{III}_xO_y^{II}\)

Theo quy tắc hóa trị: x.III = y.II

=> \(\dfrac{x}{y}=\dfrac{II}{III}=\dfrac{2}{3}\)

=> Fe₂O₃

c) \(Al^{III}_x\left(SO_4\right)^{II}_y\)

Theo quy tắc hóa trị: x.III = y.II

=> \(\dfrac{x}{y}=\dfrac{II}{III}=\dfrac{2}{3}\)

=> Al₂(SO₄)₃

d) \(H^I_xS^{II}_y\)

Theo quy tắc hóa trị: x.I = y.II

=> \(\dfrac{x}{y}=\dfrac{II}{I}=\dfrac{2}{1}\)

=> H₂S

K2CO3 (98)

Fe2O3 (160)

Al2(SO4)3 (342)

H2S (34)

`a,`

Gọi ct chung: \(\text{K}^{\text{I}}_{\text{x}}\text{Cl}^{\text{I}}_{\text{y}}\)

`@` Theo quy tắc hóa trị: \(\text{I}\cdot\text{x}=\text{I}\cdot\text{ }\rightarrow\text{ }\dfrac{x}{y}=\dfrac{\text{I}}{\text{I}}\)

`-> \text {x = 1, y = 1}`

`-> \text {CTHH: KCl}`

\(\text{PTK = }39+35,5=74,5\text{ }< \text{amu}>\)

`b,`

Gọi ct chung: \(\text{Ba}^{\text{II}}_{\text{x}}\left(\text{SO}_4\right)^{\text{II}}_{\text{y}}\)

`@` Theo quy tắc hóa trị: \(\text{II}\cdot\text{x}=\text{II}\cdot\text{y}\text{ }\rightarrow\text{ }\dfrac{x}{y}=\dfrac{\text{II}}{\text{II}}=\dfrac{1}{1}\)

`-> \text {x = 1, y = 1}`

`-> \text {CTHH:}`\(\text{BaSO}_4\)

\(\text{PTK = }137+32+16\cdot4=233\text{ }< \text{amu}>\)

NaCE

a)

                     I        II

Gọi CTTQ : Li_x(OH)_y

Li ( I ) = (OH) (I) => x = y = 1

Thay vào CTTQ : LiOH

PTK : 7 + 16 + 1 = 24

b)

                     III    II

Gọi CTTQ : Fe_xO_y

Fe ( III ) \(\ne\) O ( II ) => \(\begin{cases}x=2\\y=3\end{cases}\)

Thay vào CTTQ : Fe₂O₃

PTK : 56 . 2 + 16 . 3 =  384

Các câu c , d làm tương tự

3.1https://i.imgur.com/4xsnUiE.jpg

3.1:

- Hợp chất: \(Al_2O_3\)

- \(PTK_{Al_2O_3}\) \(= \) \(2.27 + 3.16 = 102\) (đvC)

3.2:

- Hợp chất: \(NH_3\)

- \(PTK_{NH_3}\)\( = 14 + 3.1 = 17\) (đvC)

`@` `\text {dnammv}`

`1,`

`a,` Gọi ct chung: \(\text{C}^{\text{IV}}_x\text{O}^{\text{II}}_{\text{y}}\)

Theo qui tắc hóa trị: \(\text{IV}\cdot\text{x}=\text{II}\cdot\text{y}\rightarrow\dfrac{\text{x}}{\text{y}}=\dfrac{\text{II}}{\text{IV}}=\dfrac{1}{2}\)

`-> \text {x=1, y=2}`

`-> \text {CTHH: CO}_2`

\(\text{PTK}_{\text{CO}_2}=12+16\cdot2=44\text{ }< \text{amu}>\)

`b,`

Gọi ct chung: \(\text{Na}^{\text{I}}_{\text{x}}\left(\text{SO}_4\right)^{\text{II}}_{\text{y}}\)

Theo qui tắc hóa trị: \(\text{I}\cdot\text{x}=\text{II}\cdot\text{y}\rightarrow\dfrac{\text{x}}{\text{y}}=\text{ }\dfrac{\text{II}}{\text{I}}\)

`-> \text {x=2, y=1}`

`-> \text {CTHH: Na}_2 \text {SO}_4`

a.\(SO_2,\) \(M=32+16\times2=64\)đvC

b.\(K_2CO_3,\) \(M=39\times2+12+16\times3=138\)đvC

c.\(FeCl_2,\)\(M=56+35.5\times2=127\)đvC

\(a,CTTQ:K_x^I\left(SO_4\right)_y^{II}\Rightarrow I\cdot x=II\cdot y\Rightarrow\dfrac{x}{y}=2\Rightarrow x=2;y=1\\ \Rightarrow K_2SO_4\\ PTK_{K_2SO_4}=39\cdot2+32+16\cdot4=174\left(đvC\right)\\ b,CTTQ:Zn_x^{II}Cl_y^I\Rightarrow II\cdot x=I\cdot y\Rightarrow\dfrac{x}{y}=\dfrac{1}{2}\Rightarrow x=1;y=2\\ \Rightarrow ZnCl_2\\ PTK_{ZnCl_2}=65+35,5\cdot2=136\left(đvC\right)\\ c,CTTQ:Al_x^{III}\left(NO_3\right)_y^I\Rightarrow x\cdot III=y\cdot I\Rightarrow\dfrac{x}{y}=\dfrac{1}{3}\Rightarrow x=1;y=3\\ \Rightarrow Al\left(NO_3\right)_3\\ PTK_{Al\left(NO_3\right)_3}=27+\left(14+16\cdot3\right)\cdot3=213\left(đvC\right)\\ d,CTTQ:Na_x^IO_y^{II}\Rightarrow x\cdot I=y\cdot II\Rightarrow\dfrac{x}{y}=2\Rightarrow x=2;y=1\\ \Rightarrow Na_2O\\ PTK_{Na_2O}=23\cdot2+16=62\left(đvC\right)\)

Gọi CTTQ: \(S_xO_y\)

Theo quy tắc hóa trị:

⇒ \(IV.x=II.y\)

⇒ \(\dfrac{x}{y}=\dfrac{II}{IV}=\dfrac{2}{4}=\dfrac{1}{2}\)

⇒ \(\left\{{}\begin{matrix}x=1\\y=2\end{matrix}\right.\)

CTHH: \(SO_2\)

b) Gọi CTTQ: \(Al_x\left(SO_4\right)_y\)

Theo quy tắc hóa trị:

⇒ \(III.x=II.y\)

⇒ \(\dfrac{x}{y}=\dfrac{II}{III}=\dfrac{2}{3}\)

⇒ \(\left\{{}\begin{matrix}x=2\\y=3\end{matrix}\right.\)

CTHH: \(Al_2\left(SO_4\right)_3\)

a) H₂S (34), NH₃ (17), CH₄ (16), HCl (36,5) và PH₃ (34)

b) Na₂O (62), CaO (56), Al₂O₃ (102), PbO₂ (239), SO₂ (64) và CO₂ (44)

c) K₂SO₄ (174), Al(NO₃)₃ (213), Fe(OH)₃ (107) và Ba₃(PO₄)₂ (601)

a) 

\(CTHH:H_2S\),\(NH_3,CH_4,HCl,PH_3\)

\(PTK_{H_2S}=2.1+1.32=34\left(đvC\right)\)

\(PTK_{NH_3}=1.14+3.1=17\left(đvC\right)\)

các ý còn làm tương tự

b)

\(CTHH:Na_2O,CaO,Al_2O_3,PbO_2,P_2O_5\)

\(S\) và \(C\) bạn chưa cho hóa trị thì mình chưa làm nha!

\(PTK_{Na_2O}=2.23+1.16=62\left(đvC\right)\)

\(PTK_{CaO}=1.40+1.16=56\left(đvC\right)\)

các ý còn làm tương tự

c) 

\(CTHH:K_2SO_4,Al\left(NO_3\right)_3,Fe\left(OH\right)_3,Ba_3\left(PO_4\right)_2\)

\(PTK_{K_2SO_4}=2.39+1.32+4.16=174\left(đvC\right)\)

\(PTK_{Al\left(NO_3\right)_3}=1.27+\left(1.14+3.16\right).3=213\left(đvC\right)\)

các ý còn làm tương tự