1.

Sinh ra khí H₂ và O₂

2.

\(\dfrac{V_{H_2}}{V_{O_2}}=\dfrac{2.22,4.a}{22,4.b}=\dfrac{2a}{b}\)

3.

\(\dfrac{m_{H_2}}{m_{O_2}}=\dfrac{2.2a}{32b}=\dfrac{a}{8b}\)

4.

Nước dc cấu tạo từ H và O

\(a,S_{kính}=2\left(1,2+0,8\right).0,6+1,2.0,8=4,08\left(m^2\right)\\ b,S_{đáy}=1,2.0,8=0,96\left(m^2\right)\\ h=\dfrac{0,48}{0,96}=0,5\left(m\right)\)

e: \(=\dfrac{33}{40}\cdot\dfrac{3}{4}\cdot12=\dfrac{99}{160}\cdot12=\dfrac{99\cdot3}{40}=\dfrac{297}{40}\)

g: \(=-\dfrac{9}{17}\cdot\dfrac{51}{9}\cdot\dfrac{-4}{5}\cdot\left(-19\right)==3\cdot\dfrac{4}{5}\cdot\left(-19\right)=-\dfrac{228}{5}\)

d: \(=\dfrac{-12}{25}\cdot\dfrac{-35}{18}=\dfrac{2}{3}\cdot\dfrac{7}{5}=\dfrac{14}{15}\)

\(\left(-\dfrac{1}{2}\right)^2+\dfrac{5}{8}:\dfrac{-5}{7}=\dfrac{1}{4}-\dfrac{7}{8}=-\dfrac{5}{8}\)

a: =3/2-2/3:(4/18+3/18)

=3/2-2/3:7/18

=3/2-2/3*18/7

=3/2-12/7

=-3/14

b: =(5/8-1/5)*2-1/4

=5/4-2/5-1/4

=1-2/5=3/5

c: =(3+5/6-1/2):55/12

=10/3*12/55

=8/11