Задача 1:
m(CaO) = 112 гр.
m практ. (CaCl₂) = 200 гр.
Найти:
η = ?
1) CaO + 2HCl = CaCl + H₂O
2) Находим Молярную массу реагента CaO:
n = m : M ; n = 112 : 56 = 2 моль
3) Так как на 1 моль CaСl уходит 1 моль CaO, то на 2 моль CaCl уйдет 2 моль CaO:
1 : 1 = 2 : 2
4) Теперь находим теоретическую массу продукта CaCl:
m теор. (CaCl₂) = 111 * 2 = 222 гр.
5) Теперь находим выход соли:
η = m практ. / m теор. * 100%; η = 200 * 100 / 222 = 90.1%
ответ: 90.1%.
(Такую задачу я уже решал прям минуту назад у другого человека ^_^ : )
Объяснение:
Task 1. Match the words with the opposite meaning.
1. moral a) undrinkable
2. drinkable b) shy
3. to support c) quiet
4. intense d) to bully
5. to appear e) contrary
6. similar f) to disappear
7. confident g) immoral
Task 2. Put in THE in the sentences where necessary.
1) … Mississippi is the longest river in … Northern America.
2) … Fuji is an extinct volcano and the highest mountain of … Japanese Islands.
3) … UK consists of Great Britain and … Northern Ireland.
4) … Bahamas are a group of islands in … Atlantic Ocean.
5) One of the natural attractions in … Canada is … Lake Superior.
Task 3. Choose one of these modal verbs from the box to complete the sentences.
There is one EXTRA verb.
can may should must could
need
1. When I was a little girl, I do acrobatic tricks, but now I can’t.
2. If there is not going to be any information about those passengers till tomorrow morning, we call the police.
3. Conflicts lead to bad relations.
4. We have respect for other people.
5. Do you know that cats see in the dark?
Task 4. Choose the most appropriate options to fill in the gaps.
I (1) that emergency call nearly midnight. “My three kids (2) not at home yet,” - a worried male voice informed the emergency service. The man explained that his two sons, Allan, 15, and Johnny, 13, and their twelve-year-old cousin Jack (3) for a bicycle ride and there was no sign of them yet. The man sounded very nervous, as he suspected that something (4) to the boys. No doubt, they (5) in trouble. The rescue party headed right there.
The rescuers saw the boys soon. They (6) down the hill. They were walking very slowly. Two of them were helping the third boy – his leg (7) and he was screaming with pain. Later he told us that they had been practicing extreme cycling. Unfortunately, things like that (8) quite often. I (8) for the emergency center for more than five years and have seen lots of kids suffering from their extreme. They often ignore safety rules, and get injured or worse. They cannot realize that without a very careful preparation any extreme sport is a (10) activity.
ВСТАВЬТЕ ЭТИ СЛОВА В ТЕКСТ.
1. a) receive b) received c) have received d) had received
2. a) are b) was c) were d) had been
3. a) left b) was left c) have left d) had left
4. a) happened b) had happened c) is happening d) has happened
5. a) is b) was c) were d) are
6. a) move b) are moving c) had moved d) were moving
7. a) was broken b) has been broken c) is broken d) broke
8. a) happen b) are happening c) have happened d) will happen
9. a) work b) am working c) was working d) have been working
10. a) danger b) dangerous c) dangerously d) endangered