Bài 1:

a) c) Ko phản ứng 

b) \(2KOH+CO_2\rightarrow K_2CO_3+H_2O\)

Có thể có: \(K_2CO_3+CO_2+H_2O\rightarrow2KHCO_3\)

d) \(Ba\left(OH\right)_2+CO_2\rightarrow BaCO_3+H_2O\)

Có thể có: \(BaCO_3+CO_2+H_2O\rightarrow Ba\left(HCO_3\right)_2\)

Bài 2:

\(Mg\left(OH\right)_2\underrightarrow{t^o}MgO+H_2O\)

\(2Fe\left(OH\right)_3\underrightarrow{t^o}Fe_2O_3+3H_2O\)

\(2Al\left(OH\right)_3\underrightarrow{t^o}Al_2O_3+3H_2O\)

Bài 3:

(1) \(CaCO_3\underrightarrow{t^o}CaO+CO_2\)

(2) \(CaO+H_2O\rightarrow Ca\left(OH\right)_2\)

(3) \(Ca\left(OH\right)_2+CO_2\rightarrow CaCO_3+H_2O\)

(4)  \(CaO+2HCl\rightarrow CaCl_2+H_2O\)

(5)  \(Ca\left(OH\right)_2+2HNO_3\rightarrow Ca\left(NO_3\right)_2+2H_2O\)

a) \(m_{NaOH}=60.5\%=3\left(g\right)\)

\(m_{dd}=40+60=100\left(g\right)\)

\(\Rightarrow C\%\left(NaOH\right)=\dfrac{3}{100}.100\%=3\%\)

b) \(m_{dd}=100+50=150\left(g\right)\)

\(m_{KOH}=100.20\%+50.15\%=27,5\left(g\right)\)

\(\Rightarrow C\%\left(KOH\right)=\dfrac{27,5}{150}.100\%=18,33\%\)

1.Hot and cold weather (effect) effects people in diffrent ways.

2.This professor explained his ideas with great (clear) clearly

3.Scientists consider it (belief) belives that gods create Volcanic eruptions.

4.Woman nowadays are (free) freedom of the endless cycle of child bearing and rearing.

5.The film maitained that the strike was organized by a group of political (act) actors

6.Are those (add) additives they put in food really necessary?

Bị lỗi rồi. bạn gõ lại đc ko

Gọi \(n_{H_2}=a\left(mol\right)\Rightarrow n_{H_2SO_4}=a\left(mol\right)\)

Bảo toàn khối lượng :

\(m_{hh}+m_{H_2SO_4}=m_{m'}+m_{H_2}\)

\(\Leftrightarrow22,1+98a=74,9+2a\)

\(\Leftrightarrow a=0,55\left(mol\right)\)

\(\Rightarrow V_{H_2}=0,55.22,4=12,32\left(l\right)\)

Câu 2 nhiều số lắm, ko tìm đc

Em học rút gọn phân số chưa? 4/7 là phân số tối giản của 28/49 ấy

Rút gọn \(\dfrac{28}{49}=\dfrac{28:7}{49:7}=\dfrac{4}{7}\)

\(3n+2⋮2n-1;2\in N\)

\(\Rightarrow2.\left(3n+2\right)⋮2n-1\)

\(\Rightarrow6n+4⋮2n-1\)

\(2n-1⋮2n-1;3\in N\)

\(\Rightarrow3.\left(2n-1\right)⋮2n-1\)

\(\Rightarrow6n-3⋮2n-1\)

Do vậy:

\(\left(6n+4\right)-\left(6n-3\right)⋮2n-1\)

\(\Rightarrow7⋮2n-1\)

\(\Rightarrow2n-1\inƯ\left(7\right)\)

\(\Rightarrow2n-1\in\left\{1;-1;7;-7\right\}\)

\(\Rightarrow n\in\left\{1;0;4;-3\right\}\)

1. \(\dfrac{4}{x}=\dfrac{y}{21}=\dfrac{28}{49}=\dfrac{4}{7}\Rightarrow\left\{{}\begin{matrix}\dfrac{4}{x}=\dfrac{4}{7}\\\dfrac{y}{21}=\dfrac{4}{7}\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=7\\y=12\end{matrix}\right.\)