mdd HCl = \(\frac{0.6\cdot36.5\cdot100}{10}=219\left(g\right)\)

mdd= 5.4+219-0.6=223.8 (g) ; m_{AlCl3=133.5*0.2=26.7(g)}

C%_AlCl3=

\(\frac{26.7}{223.8}\cdot100\%=11.93\%\)

a)Ta có: T = 3 + 3² + .....+ 3⁸ + 3⁹

=> T = (3 + 3² + 3³) + .... + (3⁷ + 3⁸ + 3⁹)

=> T = 3.(1 + 3 + 9) + ..... + 3⁷.(1 + 3 + 9)

=> T = 3.13 + .... + 3⁷.13

=> T = 13.(3 + .... + 3⁷) chia hết cho 13

b) Ta có: T = 3 + 3² + .....+ 3⁸ + 3⁹

=> T = (3 + 3²) + (3³ + 3⁴) + .......+ (3⁸ + 3⁹)

=> T = 3.(1 + 3) + 3³.(1 + 3) + ..... + 3⁸.( 1 + 3)

=> T = 3.4 + 3³.4 + ..... + 3⁸.4

=> T = 4.(3 + 3³ + ..... + 3⁸) chia hết cho 4

Nên T chia 4 ko có có dư

= 1

t mik nha

mik mới bị trừ 270 điểm

chủ đề của truyện lặng lẽ sapa ?

cần gấp, mơn nhìu

12+12+13+13+11

    24  +   26  +11

         50       +11

              61

ai tíck mình mình k lại

In the Mekong Delta, Long Dinh village of Tien Giang province is famous for its traditional craft of weaving flowered mats. The mat’s high quality makes them popular domestically, and they are also exported to markets worldwide including Korea, Japan and America.

In spite of its well-established reputation for this traditional craft, mat weaving only started here some 50 years ago. It was first introduced by immigrants from Kim Son, a famous mat weaving village in the northern province of Ninh Binh. However, the technique of weaving village sedge mats in Long Dinh, as compared with other places in the South, is somewhat different. Long Dinh branded mats are thicker and have more attractive colours and patterns.

Weaving sedge mats is similar to growing rice. Long Dinh mat production mainly occurs during the dry season, from January to April. Weavers have to work their hardest in May and June, otherwise, when the rainy season starts in July, they will have to put off finishing their Products till the next dry season. No matter how much work it requires, Long Dinh mat producers stick with this occupation, as it brings a higher income than growing rice.

This trade provides employment for thousands of local labourers. At present, nearly 1,000 households in Long Dinh village live on weaving mats. To better meet market demands, Long Dinh mat weavers have created more Products in addition to the traditional sedge mats. Particularly, they are producing a new type of mat made from the dried stalks of water hyacinth, a common material in the Mekong Delta.

Thanks to the planning and further investment, the mat weaving occupation has indeed brought in more income for local residents. Their living standards have improved considerably, resulting in better conditions for the whole village.

A.it has the origin from Kim Son, Ninh Binh

B.it has had the reputation for more than 50 years

C.the techniques are a little bit different from those in other regions

D.the mats have more attractive colours and designs

A.both depend on weather conditions

B.both occur on the same land

C.both bring similar incom

D.both occur at the same time

A.they can have jobs in the rainy months

B.they can go to Korea, Japan and America

C.they can make the techniques of weaving different

D.they can earn more money than growing rice

A.produce new Producs from rare material

B.for thousands of local labourers

C.try to produce various types of Products

D.stop producing the traditional sedge mats

A.the new technique makes labourers work in the dry season

B.Long Dinh mat production is only well-known in foreign markets

C.the craft contributes much to the village economy

D.most of the households in Long Dinh village live on weaving mats