a. PTHH: CuO + H₂SO₄ ---> CuSO₄ + H₂O

b. Ta có: \(n_{CuO}=\dfrac{8}{80}=0,1\left(mol\right)\)

Theo PT: \(n_{H_2SO_4}=n_{CuO}=0,1\left(mol\right)\)

=> \(m_{H_2SO_4}=0,1.98=9,8\left(g\right)\)

Ta có: \(C_{\%_{H_2SO_4}}=\dfrac{9,8}{m_{dd_{H_2SO_4}}}.100\%=4,9\%\)

=> \(m_{dd_{H_2SO_4}}=200\left(g\right)\)

c. Ta có: \(m_{dd_{CuSO_4}}=200+8=208\left(g\right)\)

Theo PT: \(n_{CuSO_4}=n_{CuO}=0,1\left(mol\right)\)

=> \(m_{CuSO_4}=0,1.160=16\left(g\right)\)

=> \(C_{\%_{CuSO_4}}=\dfrac{16}{208}.100\%=7,69\%\)

a: \(=5x^2-10x-5x^2+7x=-3x\)

b: \(=2x^3+3xy^2-4y-3xy^2=2x^3-4y\)

a.\(C\%_{KCl}=\dfrac{20}{600}.100=3,33\%\)

b.2,5kg = 2500g

\(C\%_{Al_2\left(SO_4\right)_3}=\dfrac{34,2}{2500}.100=1,368\%\)

`(a): C%_[KCl] = 20 / 600 . 100 ~~ 3,33 %`

________________________________________

`(b):` Đổi `2,5 kg = 2500 g`

`C%_[Al_2 (SO_4)_3] = [ 34,2 ] / 2500 . 100 = 1,368%`

1have to

2 had to

3shouldn't

4has to

bài 11:

a: \(\frac{15x}{7y^3}\cdot\frac{2y^2}{x^2}=\frac{15x\cdot2y^2}{7x^2y^3}=\frac{30xy^2}{7x^2y^3}=\frac{30}{7xy^{}}\)

b: \(\frac{5x+10}{4x-8}\cdot\frac{4-2x}{x+2}\)

\(=\frac{5\left(x+2\right)}{4\left(x-2\right)}\cdot\frac{-2\left(x-2\right)}{x+2}\)

\(=\frac54\cdot\left(-2\right)=-\frac52\)

c: \(\frac{1-4x^2}{x^2+4x}:\frac{2-4x}{3x}\)

\(=\frac{\left(1-2x\right)\left(1+2x\right)}{x\left(x+4\right)}\cdot\frac{3x}{2\left(1-2x\right)}\)

\(=\frac{3\left(2x+1\right)}{2\left(x+4\right)}=\frac{6x+3}{2x+8}\)

d: \(\left(\frac{1}{x^2+x}-\frac{2-x}{x+1}\right):\left(\frac{1}{x}+x-2\right)\)

\(=\left(\frac{1}{x\left(x+1\right)}+\frac{x-2}{x+1}\right):\frac{1+x^2-2x}{x}\)

\(=\frac{1+x\left(x-2\right)}{x\left(x+1\right)}\cdot\frac{x}{x^2-2x+1}\)

\(=\frac{x^2-2x+1}{x+1}\cdot\frac{1}{x^2-2x+1}=\frac{1}{x+1}\)

Giúp mik vs mọi người đâu hết rùi😄😄😄