\(mH_2SO_4=250.30\%=75g\)

\(m_{ddH_2SO_420\%}=\frac{75.100}{20}=375g\)

\(m_{H_2O}=375-250=125g\)

\(V_{H_2O}=\frac{125}{1}=125ml\)

a) \(Fe+H_2SO_4\left(\text{loãng}\right)\rightarrow FeSO_4+H_2\uparrow\)

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

c) \(4Mg+10HNO_3\rightarrow4Mg\left(NO_3\right)_2+N_2O+5H_2O\)

d) \(Al+4HNO_3\rightarrow Al\left(NO_3\right)_3+NO\uparrow+2H_2O\)

Bài 2: Muốn điều chế được 48 g O2 thì khối lượng KClO3 cần nhiệt phân là  bao nhiêu g ?

\(PTHH:\)\(2KClO_3\rightarrow^{t^o}2KCl+3O_2\)

Ta có: \(n_{O2}=\frac{48}{32}=1,5mol\)

\(\rightarrow n_{KClO_3}=\frac{1,5.2}{3}=1mol\)

\(\rightarrow m_{KClO_3}=1.122,5=122,5g\)

Vậy cân \(122,5g\)\(KClO_3\)để điều chế \(48g\)\(O_2\)

Bài 3: Muốn điều chế được 2,8 lít O2 (ở đktc) thì khối lượng KMnO4 cần nhiệt phân là bao nhiêu ?

\(PTHH:\)\(2KMnO_4\rightarrow K_2MnO_4+MnO_2+O_2\)

\(\Rightarrow n_{O2}=\frac{2,8}{22,4}=0,125mol\)

\(\Rightarrow n_{KMnO4}=\frac{0,125.2}{1}=0,25mol\)

\(\Rightarrow m_{KMnO4}=0,25.158=39,5g\)

\(Na_2O-\) Natri oxit (Oxit bazơ)

\(K_2O-\) Kali oxit (Oxit bazơ)

\(CaO-\) Canxi oxit (Oxit bazơ)

\(Fe_2O_3-\) Sắt(III) oxit (Oxit bazơ)

\(FeO-\) Sắt(II) oxit (oxit bazơ)

\(Al_2O_3-\) Nhôm oxit (oxit lưỡng tính)

\(CO_2-\) Cacbon đioxit (oxit axit)

\(P_2O_5-\) Điphotpho pentaoxit (oxit axit)

\(SO_3-\) Lưu huỳnh trioxit (oxit axit)

\(N_2O_5-\) Đinitơ pentaoxit (oxit axit)

\(HCl-\) Axit clohydric (axit)

\(H_2SO_4-\) Axit sunfuric (axit)

\(Al\left(OH\right)_3-\) Nhôm hydroxit (lưỡng tính)

\(KCl-\) Kali clorua (muối)

\(CaCO_3-\) Canxi cacbonat (muối)

\(Na_3PO_4-\) Natri photphat (muối)

\(CuSO_4-\) Đồng(II) sunfat (muối)

Gọi công thức hóa học của \(oxit\)là \(X\)

Ta có:

\(\%O=162X+16.100\%=25,8\%=0,258\)

\(\Leftrightarrow0,258.\left(2X+16\right)=16\)

\(\Leftrightarrow0,515X=11,872\)

\(\Rightarrow X\approx23\)

\(\Rightarrow X\)là \(natri\)

\(\Rightarrow CTHH\)\(oxit\)là \(Na2O\)

Dear Han!

So the busy year has passed, leaving us with so many new feelings and the chilly air on the first day of the new year. So spring has come.
The weather was cold, but it was warm, bringing with it the warmth of spring, looking out the window, the clear blue sky, the clouds, the clouds floating cotton candy sks playing with the wind. The golden, warm and smooth rays of sunlight fell to the ground. On the two sides of the road, the rows of trees were no longer bare, and instead of the young, lush buds. to welcome a spring fairy. The neighborhood I live in has been cleaned and painted. It is happy and proud to have a new outfit to welcome the New Year. Every house has red flags with yellow stars fluttering. The atmosphere of excitement, excitement to prepare for the New Year is enveloping all the space. Everything changes.

Best friend,

Huy 

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Hợp chất \(M\)\(H_3\)

\(\%H=\frac{3.1}{M+3}.100\%=17,65\%\)

\(\Leftrightarrow\frac{3}{M+3}=0,1765\)

\(\Leftrightarrow0,1765M=2,4705\)

\(\Leftrightarrow M\approx14\left(g/mol\right)\)

\(\Rightarrow Nitơ\)

What's your name?

Dịch : Tên của bạn là gì ?

Trả lời :

My name Xanh La .

my name is Trinh Tran Phuong Tuan

\(M_X=29,25.M_{H_2}=29,25.2=58,5\left(đvC\right)\)

\(\Rightarrow23x+35,5y=58,5\)  (1)

Gọi CTHH của \(X\)là:  \(Na_xCl_y\)

Ta có:

\(\frac{23x}{23x+35,5y}.100\%=39,3\%\)

\(\Rightarrow x=y\)   (2)

Từ (1) và (2) => \(x=y=1\)

Vậy CTHH của \(X\) là: \(NaCl\)