Theo thứ tự: 98, 78, 158, 164, 400, 162

\(PTK_{Ca\left(OH\right)_2}=NTK_{Ca}+2.\left[NTK_O+NTK_H\right]=40+2.\left(16+1\right)=74\left(đ.v.C\right)\\ PTK_{Fe\left(OH\right)_3}=NTK_{Fe}+3.\left[NTK_O+NTK_H\right]=56+3.\left(16+1\right)=107\left(đ.v.C\right)\\ PTK_{KNO_3}=NTK_K+NTK_N+3.NTK_O=39+14+3.16=101\left(đ.v.C\right)\\ PTK_{Fe_2O_3}=2.NTK_{Fe}+3.NTK_O=2.56+3.16=160\left(đ.v.C\right)\)

\(PTK_{N_2O_5}=2.NTK_N+5.NTK_O=2.14+5.16=108\left(đ.v.C\right)\\ PTK_{MgSO_4}=NTK_{Mg}+NTK_S+4.NTK_O=24+32+4.16=120\left(đ.v.C\right)\\ PTK_{Al_2\left(SO_4\right)_3}=2.NTK_{Al}+3.\left[NTK_S+3.4.NTK_O\right]\\ =2.27+3.\left(32+3.4.16\right)=342\left(đ.v.C\right)\\ PTK_{BaCO_3}=NTK_{Ba}+NTK_C+3.NTK_O=137+12+3.16=197\left(đ.v.C\right)\)

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

“Phân tử khối bằng tổng khối lượng của các nguyên tửu trong phân tử”

A l 2 O 3  (M = 27.2 + 16.3 = 102 đvC )

A l 2 ( S O ₄ ) 3  (M = 342 đvC ) F e ( N O 3 ) 3  ( M = 242 đvC )

N a 3 P O 4  (M = 164 đvC ) C a ( H 2 P O 4 ) 2    ( M = 234 đvC )

B a 3 ( P O 4 ) 2    (M = 601 đvC ) Z n S O 4  ( M = 161 đvC )

AgCl (M = 143,5 đvC ) NaBr ( M = 103 đvC )

\(PTK_{Mg\left(OH\right)_2}=24+\left(16+1\right).2=58\left(đvC\right)\)

\(PTK_{Ca\left(H_2PO_4\right)_2}=40+\left(1.2+31+16.4\right).2=234\left(đvC\right)\)

\(PTK_{Ba_3\left(PO_4\right)_2}=137.3+\left(31+16.4\right).2=601\left(đvC\right)\)

\(PTK_{Al_2\left(SO_4\right)_3}=27.2+\left(32+16.4\right).3=342\left(đvC\right)\)

\(PTK_{Ca\left(HCO_3\right)_2}=40+\left(1+12+16.3\right).2=162\left(đvC\right)\)

\(PTK_{Fe\left(NO_3\right)_2}=56+\left(14+16.3\right).2=180\left(đvC\right)\)

\(PTK_{Mg\left(OH\right)_2}=24+\left(16+1\right)\cdot2=58\left(đvC\right)\\ PTK_{Ca\left(H_2PO_4\right)_2}=40+\left(2+31+16\cdot4\right)\cdot2=234\left(đvC\right)\\ PTK_{Ba_3\left(PO_4\right)_2}=137\cdot3+\left(31+16\cdot4\right)\cdot2=601\left(đvC\right)\\ PTK_{Al_2\left(SO_4\right)_3}=27\cdot2+\left(32+16\cdot4\right)\cdot3=342\left(đvC\right)\\ PTK_{Ca\left(HCO_3\right)_2}=40+\left(1+12+16\cdot3\right)\cdot2=162\left(đvC\right)\\ PTK_{Fe\left(NO_3\right)_2}=56+\left(14+16\cdot3\right)\cdot2=180\left(đvC\right)\)

a) \(M_{SO_3}=32+48=80\left(DvC\right)\\ \%S=\dfrac{32}{80}.100\%=40\%\\ \%O=100\%-40\%=60\%\)

b)\(M_{CuSO_4}=64+32+16.4=160\left(DvC\right)\\ \%Cu=\dfrac{64}{160}.100\%=40\%\\ \%S=\dfrac{32}{160}.100\%=20\%\\ \%O=100\%-40\%-20\%=40\%\)

c) \(M_{H_3PO_4}=1.3+31+16.4=98\left(DvC\right)\\ \%H=\dfrac{1.3}{98}.100\%=3\%\\ \%P=\dfrac{31}{98}.100\%=31\%\\ \%O=100\%-3\%-31\%=66\%\)

d) \(M_{Al_2\left(SO_4\right)_3}=27.2+\left(32+64\right).3=342\left(DvC\right)\\ \%Al=\dfrac{27.2}{342}.100\%=15\%\\ \%S=\dfrac{32.3}{342}.100\%=28\%\\ \%O=100\%-15\%-28\%=57\%\)

a.\(\%S=\dfrac{32\times100}{32+16\times3}=40\%\)

%O = 100 - 40 = 60%

b.\(\%Cu=\dfrac{64\times100}{64+32+16\times4}=40\%\)

\(\%S=\dfrac{32\times100}{64+32+16\times4}=20\%\)

%O = 100 - 40 - 20 = 40%

c.\(\%H=\dfrac{3\times100}{3+31+64}=3.1\%\)

\(\%P=\dfrac{31\times100}{3+31+64}=31.6\%\)

%O = 100 - 3.1 - 31.6 = 65.3%

d.\(\%Al=\dfrac{54\times100}{54+96+192}=15.8\%\)

\(\%S=\dfrac{96\times100}{54+96+192}=28.1\%\)

%O = 100 - 15.8 - 28.1 = 56.1%

a,SO3:

\(\%S=\dfrac{32.100}{80}=40\%\)

\(\%O=100-40=60\%\)

b,CuSO4:

\(\%Cu=\dfrac{64.100}{160}=40\%\)

\(\%S=\dfrac{32.100}{160}=20\%\)

\(\%O=100-40-20=40\%\)

c, H3PO4:

\(\%H=\dfrac{3.100}{98}=3,1\%\)

\(\%P=\dfrac{32.100}{98}=31,6\%\)

\(\%O=100-3,1-31,6=65,3\%\)

d, Al2(SO4)3:

\(\%Al=\dfrac{27.2.100}{342}=15,8\%\)

\(\%S=\dfrac{32.3.100}{342}=28,1\%\\ \%O=100-15,8-28,1=56,1\%\)

CuO : Đồng (II) Oxit

KNO₃ : Kali Nitrat

Cu(OH)₂ : Đồng (II) hidroxit

H₃PO_{4 :} photphoric

Al₂(SO₄)₃ : Nhôm sunfat

Fe(OH)₃ : Sắt (III) hidroxit

MgSO₄ : Magie sunfat

NA₂S : Natri sunfua

HgO : Thủy ngân (II) Oxit

AgCl : Bạc clorua

KHSO₄ : Kali hiđrosunfat

HF : Axit flohidric

HNO₃ : Axit nitric

K₂CO₃ : Kali cacbonat

Mg(OH)₂ : Magie hidroxit

HNO₂ : Axit nitrơ

BaSO₄ : Bari photphat

Oxit bazơ : Fe2O3, CuO ;

Axit : H3PO4, HNO3 ;

Bazơ : KOH, Zn(OH)2 ;

Muối : ZnSO4, CuCl2, CuSO4
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