1.

a) M ($F{e}_2{O}_3$) = 2.56+3.16=160

Suy ra n ( Fe2O3)= m/M = 16/160 = 0,1 mol

b) n ( CO2) = V/22,4 = 5.36/22,4 = xấp xỉ 0,24 mol

c) n ( N2 ) = V/22,4 = 10.08/22,4 = 0,45 mol

3.

a) n (HSO2) = V/22.4 = 6,72/22,4 = 0,3 mol

Suy ra m = n.M = 0,3. 65 = 19.5g

b) n (P2O5) = m/M = 14.2/142 = 0,1 mol

Suy ra V (P2O5) = n.22,4 = 0,1.22,4 = 2,24l

$\frac{12x^{2}y(x+y)}{18xy{(x+y)}^3}=\frac{2x}{3{(x+y)}^2}$ 

( Chia cả tử và mẫu cho 6xy(x+y))

2021x-2021y+$x^2$-$y^2$

= 2021(x-y)+(x-y)(x+y)

= (x-y)(2021+x+y)

1. to swim

2. buy

3. will be leaving

4. tells; to water