Câu 1

\(n_{Fe}=\dfrac{16,8}{56}=0,3mol\\ n_{O_2}=\dfrac{2,479}{24,79}=0,1mol\\ 3Fe+2O_2\xrightarrow[t^0]{}Fe_3O_4\\ \Rightarrow\dfrac{0,3}{3}>\dfrac{0,1}{2}\Rightarrow Fe.dư\\ 3Fe+2O_2\xrightarrow[t^0]{}Fe_3O_4\)

0,15       0,1         0,05

\(m_{Fe.dư}=16,8-0,15.56=8,4g\\ b.m_{Fe_3O_4}=0,05.232=11,6g\)

Câu 2

\(n_{H_2}=\dfrac{7,437}{24,79}=0,3mol\\ R+H_2SO_4\rightarrow RSO_4+H_2\\ n_{H_2}=n_R=0,3mol\\ M_R=\dfrac{12}{0,3}=40g/mol\)

Vậy M là Canxi

PTPU: Fe + O₂ -> Fe₂O₃

Áp dụng định luật BTKL:

m_Fe + m_O2 = m_Fe2O3

=> mFe2O3 = 23,2 - 16,8 = 6,4g

=> Chọn C

PTHH: \(3Fe+2O_2\overset{t^o}{--->}Fe_3O_4\)

Ta có: \(n_{Fe}=\dfrac{16,8}{56}=0,3\left(mol\right)\)

\(n_{Fe_3O_4}=\dfrac{23,2}{232}=0,1\left(mol\right)\)

Ta thấy: \(\dfrac{0,3}{3}=\dfrac{0,1}{1}\)

=> Không có chất dư.

Theo PT: \(n_{O_2}=2.n_{Fe_3O_4}=2.0,1=0,2\left(mol\right)\)

=> \(m_{O_2}=0,2.32=6,4\left(g\right)\)

Chọn C

3Fe+2O₂-to>Fe₃O₄

0,225---0,15---0,075

n _O2= \(\dfrac{3,7185}{24,79}\)=0,15 mol

=>m _Fe=0,225.56=12,6g

=>m _Fe3O4=0,075.232=17,4g

\(n_{O_2}=\dfrac{3,7185}{24,79}=0,15\left(mol\right)\\ 3Fe+2O_2\rightarrow\left(t^o\right)Fe_3O_4\\ n_{Fe}=\dfrac{3}{2}.n_{O_2}=1,5.0,15=0,225\left(mol\right)\\ \Rightarrow m_{Fe}=0,225.56=12,6\left(g\right)\\ n_{Fe_3O_4}=\dfrac{n_{O_2}}{2}=\dfrac{0,15}{2}=0,075\left(mol\right)\\ \Rightarrow m_{Fe_3O_4}=232.0,075=17,4\left(g\right)\)

đkc đúng k bn :) ?

\(a,n_{Fe}=\dfrac{16,8}{56}=0,3\left(mol\right)\\ 3Fe+2O_2\rightarrow\left(t^o\right)Fe_3O_4\\ b,n_{Fe_3O_4}=\dfrac{n_{Fe}}{3}=\dfrac{0,3}{3}=0,1\left(mol\right)\\ \Rightarrow m_{Fe_3O_4}=232.0,1=23,2\left(g\right)\\ n_{O_2}=\dfrac{2}{3}.n_{Fe}=\dfrac{2}{3}.0,3=0,2\left(mol\right)\\ \Rightarrow V_{O_2\left(đktc\right)}=0,2.22,4=4,48\left(l\right)\)

.iron là sắt mà s cho S nx v?

a) PTHH : 3Fe + 2O₂ \(\underrightarrow{t^0}\) Fe₃O₄

b) Theo ĐLBTKL

\(m_{Fe}+m_{O_2}=m_{Fe_3O_4}\\ =>m_{O_2}=11,6-8,4=3,2\left(g\right)\)

Câu 6:

1. \(n_{O_2}=\dfrac{2,470}{24,79}=0,1\left(mol\right)\)

PTHH:

\(4Al+3O_2\rightarrow\left(t^o\right)2Al_2O_3\)

2/15    0,1              1/15

\(m_{Al}=\dfrac{2}{15}.27=3,6\left(g\right)\)

2. Gọi m KCl cần thêm là x 

Ta có:

\(15\%=\dfrac{\dfrac{10x.10}{100}+\dfrac{300.25}{100}}{10x+300}\)

\(\Rightarrow x=60\)

Vậy \(m_{ddKCl}=\dfrac{60.100}{10}=600\left(g\right)\)

\(n_{Fe_3O_4}=\dfrac{2,32}{232}=0,1\left(mol\right)\)

a)

\(3Fe+2O_2\underrightarrow{t^o}Fe_3O_4\)

0,3<--0,2<--0,1

b)

\(V_{O_2}=0,2.24,79=4,958\left(l\right)\)

c)

\(m_{Fe}=0,3.56=16,8\left(g\right)\)

4Fe+3O2-to>2Fe2O3

0,8-----0,6------0,4 mol

n Fe=\(\dfrac{44,8}{56}\)=0,8 mol

=>VO2=0,6.22,4=13,44l

=>m Fe2O3=0,4.160=64g

d) 2KMnO4-to>K2MnO4+MnO2+O2

        1,2---------------------------------0,6

=>m KMnO4=1,2.158=189,6g

a) \(n_{Zn}=\dfrac{9,75}{65}=0,15\left(mol\right)\)

PTHH: Zn + 2HCl --> ZnCl₂ + H₂

         0,15-->0,3------>0,15-->0,15

=> m_HCl = 0,3.36,5 = 10,95 (g)

b)

m_ZnCl2 = 0,15.136 = 20,4 (g)

c) 

PTHH: Fe₂O₃ + 3H₂ --t^o--> 2Fe + 3H₂O

           0,05<---0,15------->0,1

=> m_Fe2O3 = 0,05.160 = 8 (g)

m_Fe = 0,1.56 = 5,6 (g)

a.b.\(n_{Zn}=\dfrac{m_{Zn}}{M_{Zn}}=\dfrac{9,75}{65}=0,15mol\)

\(Zn+2HCl\rightarrow ZnCl_2+H_2\)

0,15    0,3           0,15     0,15            ( mol )

\(m_{HCl}=n_{HCl}.M_{HCl}=0,3.36,5=10,95g\)

\(m_{ZnCl_2}=n_{ZnCl_2}.M_{ZnCl_2}=0,15.136-20,4g\)

c.\(Fe_2O_3+3H_2\rightarrow2Fe+3H_2O\)

    0,05      0,15      0,1                      ( mol )

\(m_{Fe_2O_3}=n_{Fe_2O_3}.M_{Fe_2O_3}=0,05.160=8g\)

\(m_{Fe}=n_{Fe}.M_{Fe}=0,1.56=5,6g\)