a. biết \(PTK_{C_2}=2.12=24\left(đvC\right)\)

vậy \(PTK_{hợpchất}=24.6,5=156\left(đvC\right)\)

b. gọi CTHH của hợp chất là \(X\left(OH\right)_3\)

ta có:

\(1X+\left(1.16+1.1\right).3=156\)

\(X+51=156\)

\(X=156-51=105\left(đvC\right)\)

\(\Rightarrow\) ko có nguyên tố hóa học nào có NTK = 105, bạn kiểm tra lại đề

a. 

- Nhôm: Al

- Đồng: Cu

- Lưu huỳnh: S

- Oxi: O

b.

Đơn chất:

- N₂: \(PTK_{N_2}=14.2=28\left(đvC\right)\)

- Hg: \(NTK_{Hg}=201\left(đvC\right)\)

Hợp chất:

- KOH: \(PTK_{KOH}=39+16+1=56\left(đvC\right)\)

- Al(NO₃)₃: \(PTK_{Al\left(NO_3\right)_3}=27+\left(14+16.3\right).3=213\left(đvC\right)\)

a. VD:

Hidro kí hiệu là \(H_2\)

Cacbon kí hiệu là \(C\)

lưu huỳnh kí hiệu là \(S\)

Nito kí hiệu là \(N_2\)

b. 

đơn chất là \(N_2,Hg\) vì nó gồm những nguyên tử cùng loại liên kết với nhau

hợp chất là \(KOH,Al\left(NO_3\right)_3\) vì nó gồm những nguyên tử không cùng loại liên kết với nhau

c.

\(PTK_{N_2}=2.14=28\left(đvC\right)\)

\(PTK_{KOH}=1.39+1.16+1.1=56\left(đvC\right)\)

\(PTK_{Hg}=1.201=201\left(đvC\right)\)

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

b) Đơn chất:

    \(N_2\Rightarrow PTK=28\left(đvC\right)\)

    \(Hg\Rightarrow M=200\left(đvC\right)\)

   Hợp chất:

    \(KOH\Rightarrow PTK=39+16+1=56\left(đvC\right)\)

    \(Al\left(NO_3\right)_3\Rightarrow PTK=27+3\cdot14+9\cdot16=213\left(đvC\right)\)

Đơn chất: \(O_2\)

Hợp chất là những cái còn lại

\(M_{O_2}=32\)

\(M_{CO}=24+16=40\)

Đơn chất là : O₂ ----> PTK : 16.2= 32 DvC

Hợp chất là : CO , SO₂, Fe₂( SO₄)₃ , Al(OH)₃

\(M_{CO}=12+16=28\left(DvC\right)\\ M_{SO_2}=32+16.2=64\left(DvC\right)\\ M_{Fe_2\left(SO_4\right)_3}=56.2+\left(32+16.4\right).3=112+\left(32+64\right).3=400\left(DvC\right)\\ M_{Al\left(OH\right)_3}=27+\left(16+1\right).3=78\left(DvC\right)\)

a. gọi hóa trị của \(X\) và \(Y\) là \(x\)

\(\rightarrow X_1^xO^{II}_1\rightarrow x.1=II.1\rightarrow x=II\)

vậy \(X\) hóa trị \(II\)

\(\rightarrow Y_1^x\left(OH\right)^I_3\rightarrow x.1=I.3\rightarrow x=III\)

vậy \(Y\) hóa trị \(III\)

ta có: \(X_x^{II}Y^{III}_y\rightarrow II.x=III.y\)

\(\rightarrow\dfrac{x}{y}=\dfrac{III}{II}=\dfrac{3}{2}\rightarrow\left[{}\begin{matrix}x=3\\y=2\end{matrix}\right.\)

\(\rightarrow CTHH:X_3Y_2\)

b. ta có:

\(2X+1O=62\)

\(2X+1.16=62\)

\(2X=62-16\)

\(2X=46\)

\(X=\dfrac{46}{2}=23\left(đvC\right)\)

\(\Rightarrow X\) là\(Na\left(Natri\right)\)

\(\rightarrow CTHH:Na_2O\)

Dạng này em tính phân tử khối, nguyên tử khối rồi nhân với 0,16605.10^-23 (g)

Trả lời:

\(a)\)

\(m_C=1,6605.10^{-24}.12=1,9926.10^{-23}\left(g\right)\)

\(m_{Cl}=1,6605.10^{-24}.35,5=5,894775.10^{-23}\left(g\right)\)

\(m_{KOH}=1,6605.10^{-24}.\left(39+16+1\right)=9,2988.10^{-23}\left(g\right)\)

\(m_{H2SO4}=1,6605.10^{-24}.\left(2+32+4.16\right)=1,62729.10^{-22}\left(g\right)\)

\(m_{Fe2\left(CO3\right)3}=1,6605.10^{-24}.\left(2.56+\left(12+3.16\right).3\right)=4,84866.10^{-22}\left(g\right)\)

+) Đơn chất: \(C,Cl.\)

+) Hợp chất: \(KOH,H_2SO_4,Fe_2\left(CO_3\right)_3.\)

\(b)\)

\(m_{BaSO4}=1,6605.10^{-24}.\left(137+32+4.16\right)=3,868965.10^{-22}\left(g\right)\)

\(m_{O2}=1,6605.10^{-24}.\left(2.16\right)=5,3136.10^{-23}\left(g\right)\)

\(m_{Ca\left(OH\right)2}=1,6605.10^{-24}.\left(40+\left(16+1\right).2\right)=1,22877.10^{-22}\left(g\right)\)

\(m_{Fe}=1,6605.10^{-24}.56=9,2988.10^{-23}\left(g\right)\)

+) Đơn chất: \(O_2,Fe.\)

+) Hợp chất: \(BaSO_4,Ca\left(OH\right)_2.\)

\(c)\)

\(m_{HCl}=1,6605.10^{-24}.\left(1+35,5\right)=6,060825.10^{-23}\left(g\right)\)

\(m_{NO}=1,6605.10^{-24}.\left(14+16\right)=4,9815.10^{-23}\left(g\right)\)

\(m_{Br2}=1,6605.10^{-24}.\left(2.80\right)=2,6568.10^{-22}\left(g\right)\)

\(m_K=1,6605.10^{-24}.39=6,47595.10^{-23}\left(g\right)\)

\(m_{NH3}=1,6605.10^{-24}.\left(14+3.1\right)=2,82285.10^{-23}\left(g\right)\)

+) Đơn chất: \(Br_2,K.\)

+) Hợp chất: \(HCl,NO,NH_3.\)

\(d)\)

\(m_{C6H5OH}=1,6605.10^{-24}.\left(12.6+5.1+16+1\right)=1,56087.10^{-22}\left(g\right)\)\(m_{CH4}=1,6605.10^{-24}.\left(12+4.1\right)=2,6568.10^{-23}\left(g\right)\)

\(m_{O3}=1,6605.10^{-24}.\left(3.16\right)=7,9704.10^{-23}\left(g\right)\)

\(m_{BaO}=1,6605.10^{-24}.\left(137+16\right)=2,540565.10^{-22}\left(g\right)\)

+) Đơn chất: \(O_3\)

+) Hợp chất: \(C_6H_5OH,CH_4,BaO.\)

Bài làm:

$a)$

$m_C=1,6605.10^{-24}.12=1,9926.10^{-23}\left(g\right)$

$m_{Cl}=1,6605.10^{-24}.35,5=5,894775.10^{-23}\left(g\right)$

$m_{KOH}=1,6605.10^{-24}.\left(39+16+1\right)=9,2988.10^{-23}\left(g\right)$

$m_{H2SO4}=1,6605.10^{-24}.\left(2+32+4.16\right)=1,62729.10^{-22}\left(g\right)$

$m_{Fe2\left(CO3\right)3}=1,6605.10^{-24}.\left(2.56+\left(12+3.16\right).3\right)=4,84866.10^{-22}\left(g\right)$

+) Đơn chất: $C,Cl.$

+) Hợp chất: $KOH,H_2SO_4,Fe_2\left(CO_3\right)_3.$

$b)$

$m_{BaSO4}=1,6605.10^{-24}.\left(137+32+4.16\right)=3,868965.10^{-22}\left(g\right)$

$m_{O2}=1,6605.10^{-24}.\left(2.16\right)=5,3136.10^{-23}\left(g\right)$

$m_{Ca\left(OH\right)2}=1,6605.10^{-24}.\left(40+\left(16+1\right).2\right)=1,22877.10^{-22}\left(g\right)$

$m_{Fe}=1,6605.10^{-24}.56=9,2988.10^{-23}\left(g\right)$

+) Đơn chất: $O_2,Fe.$

+) Hợp chất: $BaSO_4,Ca\left(OH\right)_2.$

$c)$

$m_{HCl}=1,6605.10^{-24}.\left(1+35,5\right)=6,060825.10^{-23}\left(g\right)$

$m_{NO}=1,6605.10^{-24}.\left(14+16\right)=4,9815.10^{-23}\left(g\right)$

$m_{Br2}=1,6605.10^{-24}.\left(2.80\right)=2,6568.10^{-22}\left(g\right)$

$m_K=1,6605.10^{-24}.39=6,47595.10^{-23}\left(g\right)$

$m_{NH3}=1,6605.10^{-24}.\left(14+3.1\right)=2,82285.10^{-23}\left(g\right)$

+) Đơn chất: $Br_2,K.$

+) Hợp chất: $HCl,NO,NH_3.$

$d)$

$m_{C6H5OH}=1,6605.10^{-24}.\left(12.6+5.1+16+1\right)=1,56087.10^{-22}\left(g\right)\)\(m_{CH4}=1,6605.10^{-24}.\left(12+4.1\right)=2,6568.10^{-23}\left(g\right)$

$m_{O3}=1,6605.10^{-24}.\left(3.16\right)=7,9704.10^{-23}\left(g\right)$

$m_{BaO}=1,6605.10^{-24}.\left(137+16\right)=2,540565.10^{-22}\left(g\right)$

+) Đơn chất: $O_3$

+) Hợp chất: $C_6H_5OH,CH_4,BaO.$

Đơn chất: 

\(O_2-PTK:32\left(đvC\right)\\ Ba-PTK:137\left(đvC\right)\)

Hợp chất:

\(HCl-PTK:36,5\left(đvC\right)\\ BaSO_3-PTK:217\left(đvC\right)\\ NaHSO_4-PTK:120\left(đvC\right)\\ BaSO_4-PTK:233\left(đvC\right)\\ Ba\left(OH\right)_2-PTK:171\left(đvC\right)\\ H_2SO_4-PTK:98\left(đvC\right)\\ Fe\left(NO_3\right)_2-PTK:180\left(đvC\right)\\ Al_2O_3-PTK:102\left(đvC\right)\\ Fe\left(OH\right)_3-PTK:107\left(đvC\right)\)

Đơn chất: O₂, Ba

Hợp chất: HCl, BaSO₃, NaHSO₄, BaSO₄, Ba(OH)₂, H₂SO₄, Fe(NO₃)₂, Al₂O₃, Fe(OH)₃

PTK_O2 = 16.2 = 32(đvC)

PTK_HCl = 1.1 + 1.35,5 = 36,5 (đvC)

NTK_Ba = 137 (đvC)

PTK BaSO₃ = 137.1 + 32.1 + 16.3 = 217 (đvC)

PTK: NaHSO₄ = 23.1 + 1.1 + 32.1 + 16.4 = 120 (đvC)

PTK BaSO₄ = 137.1 + 32.1 + 16.4 = 233(đvC)

PTK Ba(OH)₂ = 137.1 + 16.2 + 1.2 = 171(đvC)

PTK H₂SO₄ = 1.2 + 32.1 + 16.4 = 98 (đvC)

PTK Fe(NO₃)₂ = 56.1 + 14.2 + 16.6 = 180(đvC)

PTK Al₂O₃ = 27.2 + 16.3 = 102(đvC)

PTK Fe(OH)₃ = 56.1 + 16.3 + 1.3 = 107(đvC)

cho mình hỏi cái mấy bạn ơi

1. 

\(PTK_{CuSO_4}=64+32+16.4=160\left(đvC\right)\)

\(PTK_{5CaCO_3}=5\left(40+12+16.3\right)=500\left(đvC\right)\)

\(PTK_{Ca\left(OH\right)_2}=40+\left(16+1\right).2=74\left(đvC\right)\)

2.

Theo đề, ta có:

\(d_{\dfrac{X}{Mg}}=\dfrac{M_X}{M_{Mg}}=\dfrac{M_X}{24}=\dfrac{4}{3}\left(lần\right)\)

=> M_X = 32(g)

Vậy X là lưu huỳnh (S)

3. 

Ta có: \(PTK_{Al_x\left(SO_4\right)_3}=27.x+\left(32+16.4\right).3=342\left(đvC\right)\)

=> x = 2

Bài 1.Phân tử khối các chất:

    \(CuSO_4\)\(\Rightarrow64+32+4\cdot16=160\left(đvC\right)\)

    \(CaCO_3\Rightarrow40+12+3\cdot16=100\left(đvC\right)\)

    \(Ca\left(OH\right)_2\Rightarrow40+16\cdot2+2=74\left(đvC\right)\)

Bài 2.Theo bài: \(\overline{M_X}=\dfrac{4}{3}\overline{M_{Mg}}=\dfrac{4}{3}\cdot24=32\left(đvC\right)\)

     Vậy X là lưu huỳnh.KHHH: S.

Bài 3. \(Al_x\left(SO_4\right)_3\) \(\Rightarrow27x+3\cdot\left(32+4\cdot16\right)=342\Leftrightarrow x=2\)

Bt làm , nhưng mà cần gấp hôm ??

a)

Do R hóa trị III liên kết với OH

=> CTHH: R(OH)₃

 \(PTK_{R\left(OH\right)_3}=39.2=78\left(đvC\right)\)

b) Ta có: \(NTK_R+\left(NTK_O+NTK_H\right).3=78\)

=> \(NTK_R+\left(16+1\right).3=78\)

=> \(NTK_R=27\left(đvC\right)\)

=> R là Al (Nhôm)

CTHH: Al(OH)₃