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\(n_{Na_2CO_3}=\dfrac{10.6}{106}=0.1\left(mol\right)\)

\(n_{BaCl_2}=\dfrac{250\cdot20.8\%}{208}=0.25\left(mol\right)\)

\(BaCl_2+Na_2CO_3\rightarrow BaCO_3+2NaCl\)

\(1.................1\)

\(0.25.............0.1\)

\(LTL:\dfrac{0.25}{1}>\dfrac{0.1}{1}\Rightarrow BaCl_2dư\)

\(n_{BaCO_3}=n_{Na_2CO_3}=0.1\left(mol\right)\)

\(m_{BaCO_3}=0.1\cdot197=19.7\left(g\right)\)

\(m_{\text{dung dịch sau phản ứng}}=10.6+250-19.7=240.9\left(g\right)\)

\(C\%_{NaCl}=\dfrac{0.2\cdot58.5}{240.9}\cdot100\%=4.85\%\)

a) 

Na₂CO₃+BaCl₂------>BaCO₃+2NaCl

B) n_NaCO3 =0,1(mol)

=>m_BaCo3= 0,1*(137+12+16*3)=19,7(g)

a)       Na₂CO₃ + BaCl₂ → 2NaCl + BaCO₃↓

b)   nNa₂CO₃ = \(\dfrac{10,6}{106}\) = 0,1 mol

   mBaCl₂ = \(\dfrac{250.20,8}{100}=52\) gam

  nBaCl₂ = \(\dfrac{52}{208}=0,25\) mol

                Na₂CO₃ + BaCl₂ → 2NaCl + BaCO₃↓

Ban đầu:     0,1        0,25 

Pư:             0,1         0,1             0,2         0,1

Sau pư:       0           0,15           0,2         0,1

mBaCO₃ = 0,1.197=19,7 gam

c)   mdd= 10,6+250-19,7=240,9 gam

C%_NaCl = \(\dfrac{0,2.58,5}{240,9}.100\%=4,86\%\)

1 Facsimile was invented by Alexander Bain

2 Ha Long Bay was recognized as one of the world's seven wonders

3 Can garbage be used to make compost?

4 Romeo and Juliet was written by Shakespeare in 1592 

5 Did the Wright brothers build the first plane in 1903?

6 Our factory doesn't produce this kine of paper

7 People have used ball point pens for many years

7 Whitcomb L.Judsin invented the zipper in 1893

1 about - in

2 In - to

3 from - of - in

4 in - at - during

5 in - on

6 about

7 from

8 as

9 by - in - in

10 to - in

IV

1 moon

2 when

3 for

4 from

5 living

6 understands

7 hungry

8 developes

VI

1 is written

2 is folded

3 is put

4 is sent

5 is collected

6 is sorted 

7 is taken

8 is delivered

IV

1 moon

2 when

3 for

4 from

5 living

6 understands

7 hungry

8 developes

VI

1 is written

2 is folded

3 is put

4 is sent

5 is collected

6 is sorted 

7 is taken

8 is delivered

gửi bạn nha

a) 900 cm² = 0,9 m²

Diện tích căn phòng:

9 × 4 = 36 (m²)

Số viên gạch cần dùng lát kín căn phòng:

36 : 0,9 = 40 (viên)

b) Số tiền mua gạch:

40 : 5 × 20000 = 160000 (đồng)

XI

1 That book was published a few years ago

2 The magazines are put on the shelf in the corner

3 These toys are sold on Disneyland and in Hong Kong

4 My house was built in 2001

5 This computer was made in China

6 These old clothes are collected for the poor children.

7 This reports had been finished by five o'clock

8 Nam said he would attend the lecture last night

XI.1. That book/ publish/ a few years ago

--> That book was published a few years ago

2. The magazines/ put/ shelf/ the corner 

--> The magazines are put on the sheft in the corner

3. These toys/ sell/ Disneyland/ Hong Kong

--> These toys are sold at Disneyland in Hong Kong

4. My house/ build/ 2001

--> My house was built in 2001

5. This computer/ make/ China

--> This computer is made in China

6. These old clothes/ collect/ the poor children

--> These old clothes are collected for the poor children

7. These reports/ finish/ by / 5 o'clock

--> These reports are finish by him/her at 5 o'clock

8. Nam/ said/ he/ attend/ the lecture/ that night

--> Nam said he attended the lecture that night

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