giúp mk vs ạ
K
Khách
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MM
27 tháng 2 2022
A song was sung by her.
Was the letter sent by him?
The bus was stopped.
My car was stolen by a thief.
He was not let go.
H
11 tháng 8 2021
Câu 1 :
Gọi $m_{dd} = a(gam)$
$n_{NaOH} = \dfrac{a.20\%}{40} = 0,005a(mol)$
$n_{Ba(OH)_2} = \dfrac{a.8,55\%}{171} = 0,0005a(mol)$
$n_{HNO_3} = \dfrac{224}{1,1.1000}.4,5 = 0,9(mol)$
$NaOH + HNO_3 \to NaNO_3 + H_2O$
$Ba(OH)_2 + 2HNO_3 \to Ba(NO_3)_2 + 2H_2O$
Theo PTHH :
$0,005a + 0,0005a.2 = 0,9 \Rightarrow a = 150(gam)$
H
11 tháng 8 2021
Câu 2 :
Gọi thể tích dung dịch cần tìm là V(lít)
$n_{H_2SO_4} = 1,1V(mol) ; n_{HCl} = 1,98V(mol)$
$\Rightarrow n_H = 1,1V.2 + 1,98V = 4,18V(mol)$
$n_{NaOH} = 0,19.3 = 0,57(mol) ; n_{Ba(OH)_2} = 0,19.4 = 0,76(mol)$
$\Rightarrow n_{OH} = 0,57 + 0,76.2 = 2,09(mol)$
$H + OH \to H_2O$
$\Rightarrow 4,18V = 2,09 \Rightarrow V = 0,5(lít)$
30 tháng 8 2021
a,NTK của Y là:1,5.16=24 (g/mol)
NTK của X là: \(\dfrac{1}{2}.24=12\left(g/mol\right)\)
b,KHHH của X là C
của Y là Mg
của Z là O
19 tháng 1 2022
1. She usually wears a red uniform.
2. There was a concert yesterday.
S
19 tháng 1 2022
We went to the dinosaur museum
A farmer found Son Doong Cave in 1991
This is hers jacket
19 tháng 1 2022
1. We went to the dinosaur museum
2.A farmer found Son Doong Cave in 1991
3.This jacket is hers
DT
1
DT
10 tháng 12 2021
8. Cu(OH)2+H2SO4=>CuSO4+2H2O
9, FeO+2HCl2=>FeCl2+H2O
10, Fe2O3+3H2SO4=>Fe2(SO4)3+3H2O
11, Cu(NO3)2+2NaOH=>Cu(OH)2+2NaNO3
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