program tim_dien_tich;

uses crt;

var a1,a2,b1,b2,x1,x2,i,dem:longint;

dtnn,dt1,dt2,dt3,dt4,dt5,dt6:real;

x3:array[1..1000]of longint;

dt:array[1..1000]of real;

begin

  clrscr;

  write('nhap chieu dai va chieu rong:');readln(a1,b1);

  a2:=a1;b2:=b1;dt1:=a1*b1;dt2:=dt1/2;

  x1:=0;i:=0;dem:=0;

  writeln(dt2:5:1);

  writeln(x1);

  while x1<b1 do

  begin

    dt3:=a2*x1/2;

    dt4:=(b2-x1)*x1/2;

    dt5:=b2*(a2-x1)/2;

    dt6:=dt1-dt3-dt4-dt5;

    dt[i]:=dt6;x3[i]:=x1;

    x1:=x1+1;i:=i+1;dem:=dem+1;

  end;

  dtnn:=dt[1];

  for i:=1 to dem do

  begin

    if (dtnn>dt[i])and(dt[i]<>0) then dtnn:=dt[i];

  end;

  writeln(dtnn:5:1);

  for i:=1 to dem do

  if dtnn=dt[i] then writeln(x3[i]);

  readln;

end.

m Fe=0,2.56=11.2g

mCu=0,5.64=32g

b)n CO=11,2\22,4=0,5mol

n CO2=33,6\22,4=0,15 mol

=>m hh=0,5.28+0,15.44=20,6g

Câu 3.

\(n_{CO_2}=\dfrac{33,6}{22,4}=1,5mol\)

Gọi \(\left\{{}\begin{matrix}n_{CH_4}=x\\n_{C_2H_4}=y\end{matrix}\right.\)

\(CH_4+2O_2\rightarrow\left(t^o\right)CO_2+2H_2O\)

   x                              x                   ( mol )

\(C_2H_4+3O_2\rightarrow\left(t^o\right)2CO_2+2H_2O\)

  y                                 2y              ( mol )

Ta có:

\(\left\{{}\begin{matrix}22,4x+22,4y=22,4\\x+2y=1,5\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}x=0,5\\y=0,5\end{matrix}\right.\)

\(n_{hh}=\dfrac{22,4}{22,4}=1mol\)

\(\%V_{CH_4}=\dfrac{0,5}{1}.100=50\%\)

\(\%V_{C_2H_4}=\dfrac{0,5}{1}.100=50\%\)

Câu 2.

\(n_{CO_2}=\dfrac{8,96}{22,4}=0,4mol\)

\(n_{hh}=\dfrac{6,72}{22,4}=0,3mol\)

Gọi \(\left\{{}\begin{matrix}n_{CH_4}=x\\n_{C_2H_4}=y\end{matrix}\right.\)

\(CH_4+2O_2\rightarrow\left(t^o\right)CO_2+2H_2O\)

  x                             x                      ( mol )

\(C_2H_4+3O_2\rightarrow\left(t^o\right)2CO_2+2H_2O\)

   y                              2y                    ( mol )

Ta có:

\(\left\{{}\begin{matrix}x+y=0,3\\x+2y=0,4\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}x=0,2\\y=0,1\end{matrix}\right.\)

\(\%V_{CH_4}=\dfrac{0,2}{0,3}.100=66,66\%\)

\(\%V_{C_2H_4}=100\%-66,66\%=33,34\%\)

úi , chụp có độ sáng zới , nhìn vậy hỏng mắt mất

a

Bài 1: 

a: \(=x^2+x+x^2-5x+6=2x^2-4x+6\)

\(KMnO_4+FeSO_4+H_2SO_4\rightarrow MnSO_4+Fe_2\left(SO_4\right)_3+K_2SO_4+H_2O\)

\(5\times\) \(2Fe^{+2}\rightarrow2Fe^{+3}+2e\)

\(2\times\)\(Mn^{+7}+5e\rightarrow Mn^{+2}\)

\(2KMnO_4+10FeSO_4+8H_2SO_4\rightarrow2MnSO_4+5Fe_2\left(SO_4\right)_3+K_2SO_4+8H_2O\)

cân bằng nhá

\(2KMnO_4 + 10FeSO_4 + 8H_2SO_4 \to 2MnSO_4 + 5Fe_2(SO_4)_3 + K_2SO_4 + 8H_2O\)