ủa đòi bao h .-.

có thưởng coin hong

`1,42:0,5+1,42xx8`

`=1,42xx2+1,42xx8`

`=1,42xx(2+8)`

`=1,42xx10`

`=14,2`

`12,35 xx15-1,235xx10xx6+12,35`

`=12,35xx15-12,35xx6+12,35`

`=12,35xx(15-6+1)`

`=12,35xx10`

`=123,5`

a)`1,25 + 1,25 xx 2 + 7 xx 1,25=1,25 xx (1+2+7) = 1,25 xx 10 =12,5`

b)`3,62xx12–2xx0,362xx10=3,62 xx 12 -2 xx 3,62=3,62xx(12-2)=3,62xx10=36,2`

c)`12,35xx15–1,235xx10xx6+12,35=12,35xx15–12,35xx6+12,35=12,35xx(15-6+1)=12,35xx10=123,5`    

d)`1,42 : 0,5 + 1,42 xx 8=1,42xx2+1,42xx8=1,42xx(2+8)=1,42xx10=14,2`

uk

\(m_{Al}=\dfrac{21,6}{27}=0,8\left(mol\right)\)

PTHH: 4Al+3O₂\(\underrightarrow{t^o}\)2Al₂O₃

           0,8    0,6        0,4       (mol)

\(V_{O_2}=0,6.22,4=13,44\left(l\right)\\ m_{Al_2O_3}=0,4.102=40,8\left(g\right)\\ V_{kk}=13,44.5=67,2\left(l\right)\)

bạn làm sai r

` 52,6 xx 14 – 5,26 xx 5 xx 10 + 52,6`

`= 52,6 xx 14 – 52,6 xx 5  + 52,6`

` =52,6 xx (14–5+1)`

`=52,6 xx 10`

`=526`

gợi ý đi .-.