tìm x, biết:
a, x (6x -2)= (3x-2) (2x + 7)
b, -2 (3x+1) + 4 (2x+3)= -5 (x-1)
c, (3x-1) (4x+3) = (5-2x) (7-6x)
d, 2 (3-2x) = 5 (2x-3) - 3 (4x-1)
a)
PTHH:
\(CuO+H_2SO_4\rightarrow CuSO_4+H_2O\)
\(Cu+2H_2SO_{4\left(đ,n\right)}\rightarrow CuSO_4+SO_2+2H_2O\)
b) \(n_{SO_2}=\dfrac{1,12}{22,4}=0,05\left(mol\right)\)
PTHH: \(Cu+2H_2SO_{4\left(đ,n\right)}\rightarrow CuSO_4+SO_2+2H_2O\)
0,05<---------------------------0,05
=> \(\%m_{Cu}=\dfrac{0,05.64}{10}.100\%=32\%\Rightarrow\%m_{CuO}=100\%-32\%=68\%\)
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a)
\(CuO+H_2SO_{4\left(loãng\right)}\rightarrow CuSO_4+H_2O\\ Cu+2H_2SO_{4\left(đặc,nóng\right)}\rightarrow CuSO_4+SO_2+2H_2O\)
b)
\(n_{Cu}=n_{SO_2}=\dfrac{1,12}{22,4}=0,05\left(mol\right)\\ \Rightarrow\left\{{}\begin{matrix}\%m_{Cu}=\dfrac{0,05.64}{10}.100\%=32\%\\\%m_{CuO}=100\%-32\%=68\%\end{matrix}\right.\)
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3 u
4 u
5 c
6 c
7 c
8 u
9 c
10 c
11 u
12 c
13 u
14 c
15 u
16 u
17 u
18 u
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20 c
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1 no i am not (???)
2 Yes I am
3 No it isn't
4 yes I am
5 no it isn't
6 no I am not (???)
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1 didn't have
2 weren't
3 lived
4 could travel
5 were
6 didn't have to
7 could fly
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