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\(a.n_{Al_2O_3}=\dfrac{10,2}{102}=0,1\left(mol\right)\\ PTHH:Al_2O_3+6HCl\rightarrow2AlCl_3+3H_2O\\ 0,1...........0,6..........0,2.......0,3\left(mol\right)\\ b,m_{AlCl_3}=0,2.133,5=26,7\left(g\right)\\ c.m_{ddsau}=10,2+400=410,2\left(g\right)\\ d.C\%_{ddAlCl_3}=\dfrac{26,7}{410,2}.100\approx6,509\%\)

24 tháng 8 2021

Bài 3 : 

                                   Số  mol của nhôm oxit

                                 nAl2O3 = \(\dfrac{m_{Al2O3}}{M_{Al2O3}}=\dfrac{10,2}{102}=0,1\left(mol\right)\)

Pt :                      Al2O3 + 3H2SO4 → Al2(SO4)3 + 3H2O\(|\)

                             1              3                  1                3

                            0,1          0,3                0,1

a)                                      Số mol của axit sunfuric

                                      nH2SO4 = \(\dfrac{0,1.3}{1}=0,3\left(mol\right)\)

                                       Khối lượng của axit sunfuric

                                      mH2SO4 = nH2SO4 . MH2SO4

                                                    = 0,3 . 98

                                                     = 29,4 (g)

                      Nồng độ phần trăm của dung dịch axit sunfuric

                          C0/0H2SO4 = \(\dfrac{m_{ct}.100}{m_{dd}}=\dfrac{29,4.100}{400}=7,35\)0/0

b)                           Số mol của muối nhôm sunfat

                              nAl2(SO4)3 = \(\dfrac{0,3.1}{3}=0,1\left(mol\right)\)

                              Khối lượng của nhôm sunfat

                         mAl2(SO4)3 = nAl2(SO4)3 . MAl2(SO4)3

                                           = 0,1 . 342

                                          = 34,2 (g)

c)                        Khối lượng của dung dịch sau phản ứng

                        mdung dịch sau phản ứng = mAl2O3 + mH2SO4

                                                            = 10,2 + 400

                                                             = 410,2 (g)

 d)                     Nồng độ phần trăm của muối nhôm sunfat

                         C0/0Al2(SO4)3 = \(\dfrac{m_{ct}.100}{m_{dd}}=\dfrac{34,2.100}{410,2}=8,34\)0/0

  Chúc bạn học tốt

15 tháng 5 2022

học như bình thường:)

15 tháng 5 2022

mỗi người sẽ có một cách học khác nhau. cách học mấy môn đó của mik là dành ra mấy ngày nghỉ để học hết những môn đó.

9 tháng 12 2021

1d

2d

9 tháng 12 2021

1 đúng 2 d

Mọi người ơi giúp em chọn đáp án đúng kèm giải thích chi tiết lý do vì sao chọn giúp em với ạ! Em cảm ơn rất nhiều ạ.11. I'm grateful that you helped my brother do that work.A. Thank you for helping my brother do that work.B. Thank you about helping my brother do that work.C. Thank you because you helped me do that work.D. Thank you that you help my brother do that work12. I find it impossible not to worry about Lan.A. I can't help feeling worried about LanB. Ifeel...
Đọc tiếp

Mọi người ơi giúp em chọn đáp án đúng kèm giải thích chi tiết lý do vì sao chọn giúp em với ạ! Em cảm ơn rất nhiều ạ.

11. I'm grateful that you helped my brother do that work.
A. Thank you for helping my brother do that work.
B. Thank you about helping my brother do that work.
C. Thank you because you helped me do that work.
D. Thank you that you help my brother do that work
12. I find it impossible not to worry about Lan.
A. I can't help feeling worried about Lan
B. Ifeel worried about Lan, but I can't do anything to help
C.I can't do nothing to help Lan although I feel worried about her
D. I'm unable to worry about Lan
13. You'd better take a taxi; it was raining hard outside
A. You'd better take a taxi in case it was raining
B. She advised us to take a tad because it was raining outside
C. She gave us a lift because it was raining heavily
D. She didn't lend us any raincoats but a taxi
14. My brother and I go to that school
A. I went to that school and my brother, too
B. I went to that school and so my brother did
C. I went to that school and so did my brother
D. I went to that school and so my brother did, too
15. The meeting was put off because of pressure of time
A. There was not enough time to hold the meeting
B. People wanted to get away, so the meeting began early
C. The meeting was planned to start in a short time
D. The meeting lasted much longer than usual
16. When they arrived, the good seats were already taken
A. They didn't get good seats because they arrived too late
B. They arrived late enough to get good seats
C. They had to stand for the whole show
D. We couldn't get good seats although we arrived early
17. They would never have accepted his money if they had known his plans
A. They knew what he wanted to do, so they refused his money
B. They agreed with his wishes because they were glad to have his money
C. They didn't know his plans and never took money from him
D. They took the money be offered them without realizing
18. He could not afford to buy the car
A. He couldn't buy the car because it was too expensive
B. He bought the car because it was expensive
C. He bought the car though it was expensive
D. He had enough money but he didn't buy the car
19. Tam is not good at English and neither am I
A. Neither Tam nor I am good at English
B. Either Tam or I am good at English
C. I'm not as good at English as Tam is
D. Tam isn't good at English but I am
20. This is the first time I attend such an exciting holiday.
A. The first holiday I attended was exciting.
B. I had the first exciting holiday.
C. My attendance at the first holiday was exciting.
D. I have never attended such an exciting holiday before.

0
4 tháng 12 2016

27.39 + 27.63 - 3.27

= 27 x ( 39 + 63 - 3 )

= 27 x 99

= 2673

4 tháng 12 2016

27 x 39 + 27 x 63 - 3 x 27

= 27 x ( 39 + 63 - 3 )

= 27 x  99

= 2673

4:

\(M=1+\dfrac{1}{2}+...+\dfrac{1}{2^{99}}+\dfrac{1}{2^{99}}\)

\(=1+\dfrac{1}{2}+...+\dfrac{1}{2^{98}}+\dfrac{2}{2^{99}}\)

=...

=2

3:

a: \(=\left(\dfrac{2}{48}-\dfrac{15}{48}\right)\cdot\dfrac{-8}{3}+1\)

=13/48*8/3+1

=13/18+1=31/18

b: \(=\dfrac{-5}{7}:\left(1-\dfrac{4}{7}\right)+\dfrac{46}{3}\cdot\dfrac{-1}{23}\)

=-5/7:3/7+-2/3

=-2/3-5/3=-7/3

c: =A*(1/49-1/7^2)=0

e: =1/2*2/3*...*2019/2020=1/2020

NV
17 tháng 12 2020

Định lý hàm cosin:

\(BD=\sqrt{AB^2+AD^2-2AB.AD.cos\widehat{BAD}}=2\sqrt{7}\)

30 tháng 6 2021

25. The children are going to school on foot now

28. How much does a bottle of cooking oil cost?

30 tháng 6 2021

24. is in front of the supermarket.

25. walk to school now.

26. is taller than Nam.

27. don't we go camping in Suoi Mo?

28. a bottle of cooking oil cost?

11 tháng 6 2021

1 D

2 C

3 D

11 tháng 6 2021

Thank you <3