ответ: 1. there is a big tree in the garden. 2. there is a bank
near here. - where is bank? 3. there is a new
supermarket in the center of our town. 4. there is a hotel
over there. hotel isn't cheap. 5. where is the cat?
cat is on the sofa. 6. where is the book? - book is on the
shelf. 7. where are the flowers? - flowers are in a
beautiful vase. 8. where is the vase? - the vase is on a little table near the window. 9. open the window, please. the weather is fine today. i can see
sun in the sky, i can see a nice little bird. bird is
sitting on a big tree. the tree is green. 10. there is a
little white cloud in the sky. 11. we have a large room.
there is a big sofa in the room and a little lamp on
wall over the sofa. i like to sit on the sofa and read a good book.
ответ: 1. there is a big tree in the garden. 2. there is a bank
near here. - where is bank? 3. there is a new
supermarket in the center of our town. 4. there is a hotel
over there. hotel isn't cheap. 5. where is the cat?
cat is on the sofa. 6. where is the book? - book is on the
shelf. 7. where are the flowers? - flowers are in a
beautiful vase. 8. where is the vase? - the vase is on a little table near the window. 9. open the window, please. the weather is fine today. i can see
sun in the sky, i can see a nice little bird. bird is
sitting on a big tree. the tree is green. 10. there is a
little white cloud in the sky. 11. we have a large room.
there is a big sofa in the room and a little lamp on
wall over the sofa. i like to sit on the sofa and read a good book.
объяснение:
думаю так, но всё равно проверь
2. Химические явления:
а) б)
3.
1) — Б
2) — Г
3) — А
4) — В
4.
CO2 — валентность углерода (C) = 4 (сверху пишешь над углеродом римскую цифру 4) , кислорода (О2) = 2, (точно также, римскую 2)
SiH4 — валентность кремния (Si) = 4, водорода = 1.
Cl2O7 — валентность хлора (Cl2) = 7, кислорода = 2.
Na2O — валентность натрия (Na) = 1. валентность кислорода = 2.
5. Дано:
Na2CO3
Найти:
w (C) =?
Решение:
сначала рассчитаем молярную массу.
M (Na2CO3) = 23 * 2 + 12 + 16 * 3 = 106
теперь находим массовую долю углерода,
w (C) = Ar(C) * n / Mr(Na2CO3) *100% = 12 / 106 *100% = 11,3%
ответ: 11,3%
6.
А) SO3 + H2O = H2SO4 (соединение)
Б) 2CH4 + O2 = 2CO + 4H2 (горение, соединение)
7.
1) 2H2O = 2H2 + O2
2) 3O2 + 4Al = 2Al2O3
3) 5O2 + 4P = 2P2O5
8.
Дано:
m р-ра (MgCl2) = 120 г
w р-pa (MgCl2) = 8% = 0,08
Найти:
m в-ва (NaCl) = ?
m (воды) =?
Решение:
итак, будем использовать формулу массовой доли:
w = m (в-ва) / m (р-ра)
выразим m (в-ва) :
m (в-ва) = m (p-pa) * w
m (NaCl) = 120 * 0,08 = 9,6 г
m (воды) = m (р-ра) — m (в-ва)
m (H2O) = 120 — 9,6 = 110,4 г
ответ: m соли, (NaCl) = 9,6 г, m воды (H2O) = 110,4 г.
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