Đáp án:
Giải thích các bước giải:
Gọi CTHH là KxCly
$\frac{MKx}{%K}$ = $\frac{MCly}{%Cl}$ = $\frac{x}{y}$
⇒ $\frac{x}{y}$ = $\frac{52,35 * 35,5}{47,65 * 39}$ = 1
Vậy CTHH là KCl
Gọi CTHH của muối là : `K_xCl_y`
Ta có : `x -: y = (52,35)/39 -: (47,65)/(35,5) = 1,34 -: 1,34 = 1 : 1`
`to` $\begin{cases}x=1\\y=1\end{cases}$
`to` CTHH của muối là : `KCl`
Giúp!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Mn ơi giúp em vs ạ! Cho phương trình: x^2 -2(m+1) x+m^2 -4=0 (1) (m là tham số ). Tìm m để pt (1) Có 2 nghiệm phân biệt x1, x2 thỏa mãn: x1^2 + 2(m+1) x2 +m^2 - 4 = 0
Bài 2. Bỏ dấu ngoặc rồi tính a, -7264 + (1543 + 7264) g, (36 + 79) + (145 – 79 – 36) b, (144 – 97) – 144 h, 10 – [12 – (- 9 - 1)] c, (-145) – (18 – 145) i, (38 – 29 + 43) – (43 + 38) d, 111 + (-11 + 27) k, 271 – [(-43) + 271 – (-17)] e, (27 + 514) – (486 – 73) m, -144 – [29 – (+144) – (+144)]
B. READING Exercise 1: Read the text below and decide which answer A, B, C or D best fits each space» If you're an environmentalist, plastic is a word you tend to say with a sneer or a snarl. It has become a symbol of our wasteful, throw-way society. But there seems little (1)… it is here to stay, and the truth is, of course, that plastic has brought enormous (2) …………..even environmental ones. It's not really the plastics themselves that are the environmental (3) ………….. - it's the way society choose to use and (4) them. Almost all the 50 or so different kinds of modern plastic are made from oil, gas or coal - non-renewable natural (5) ………….. We (6) well over three million tones of the stuff in Britain each year and, sooner or later, most of it is thrown away. A high (7) ………….. of our annual consumption is in the way of packaging, and this constitutes about seven per cent by weight of our domestic (8) ………….. Almost all of it could be recycled, but very little of it is, though the plastic recycling (9) is growing fast. The plastics themselves are extremely energy-rich - they have a higher calorific value than coal and one method of 'recovery' strongly desired by the plastic manufacturers is the (10) …………..of waste plastic into a fuel. 1. A. evidence B. concern C. doubt D. likelihood 2. A. pleasures B. benefits C. savings D. profits 3. A. poison B. disaster C. disadvantage D. evil 4. A. dispose B. store C. endanger D. abuse 5. A. resources B. processes C. products D. fuels 6. A. remove B. import C. consign D. consume 7. A. portion B. amount C. proportion D. rate 8. A. refuse B.goods C. requirements D. rubble 9. A. manufacture B. plant C.factory D. industry 10. A. conversion B. melting C. change D. replacement Exercise 2: Read the text carefully and choose the best answers (A, B, C or D) to these questions The natural world is under violent assault from man. The sea and rivers are being poisoned by radioactive wastes, by chemical discharges and by the dumping of dangerous toxins and raw sewage. The air we breathe is polluted by smokes and fume from factories and motor vehicles. Even the rain is poisoned. It's little wonder forests and lakes are being destroyed and everywhere wildlife is disappearing. Yet the destruction continues. Governments and industries throughout the world are intensifying their efforts to extract the earth mineral riches and to plunder its living resources. The great rain forests and the frozen continents alike are seriously threatened.And this despite the warnings of the scientific community and the deep concern of millions of ordinary people. Despite the fact, too, that we can create environmentally - clean industries, harness the power of the sun, wind and waves for our energy needs and manage the finite resources of the earth in a way that will safeguard our future and protect all the rich variety of life forms which share this planet with us. But there I still hope. The forces of destruction are being challenged across the globe - and at the spearhead of this challenge is Greenpeace. Wherever the environment is in danger, Greenpeace has made a stand. Its scientific presentations and peaceful direct actions at sea and on land have shocked governments and industries into an awareness that Greenpeace will not allow the natural world to be destroyed. Those actions, too, have won the admiration and support of millions. Now you can strengthen the thin green line; you can make your voice heard in defence of the living world by joining Greenpeace today .Thank God someone's making waves. 1. Which one of these statements is not made? A. Drinking water is polluted. B. Radioactive waste poisons the sea. C. Sewage isn't processed. D. Cars and factories pollute the air. 2. The writer… forests and lakes are being destroyed. A. is surprised that B. is unsure why C. wonders why D. understands why 3. Rain forests are being destroyed because governments and industries………….. A. are unaware of what they are doing wrong B. are rich and powerful C. choose to ignore criticism D. basically care about the environment 4. The earth's resources………….. A. should be left for people B. can be made to last longer C. will last forever D. belong to just humans and animals 5. How does Greenpeace feel about the future? A. Desperate. B. Resigned. C. Cautiously optimistic. D. Deeply pessimistic. 6. Governments and industries………….. A. don't know what Greenpeace thinks B. misunderstand what Greenpeace thinks C. can easily ignore Greenpeace D. are forced to understand the problems by Greenpeace 7. How does Greenpeace think that people can help? A. By becoming members. B. By speaking out. C. By painting a green line. D. By making waves C. WRITING
VIII. Rewrite each of the following sentences in such a way that means exactly the same as the sentence printed before it. (2.0 points) 1. You forget to turn off the TV last night, didn’t you? You didn’t remember ............................................................................................ 2. I think you should go to work by bike. Why don’t ............................................................................................................. 3. We will plant more trees along this street. More trees ............................................................................................................. 4. They will build a new school for poor children next month. A new school ........................................................................................................ 5. Mr Long lived in the country when he was a child. Mr Long used ........................................................................................................
Làm giúp em với ạ,đang cần gấp Làm ngắn nhưng đủ ý giúp e với ạ !
VII. Put the words and phrases in the right order to make meaningful sentences. (1.0 point) 1. more/ because/ People/ cheap/solar/ should/ it/ unlimited/ use/ and energy/ clean/ is/. .............................................................................................................................. 2. she/ is/ aunt/ Although/ lives/ my/ poor/ happily/. .............................................................................................................................. 3. is/ Driving/ dangerous/ fast/ very/. .............................................................................................................................. 4. live/ Many/ the/ people/ country/ prefer/ in/ to/. .............................................................................................................................. 5. traffic/ are/ rush-hours/ always/ There/ jams/ during/.
Câu 20: Theo em các cuộc kháng chiến, khởi nghĩa chống ngoại xâm của nhân dân ta từ thế kỉ X đến thế kỉ XV thắng lợi là do những nguyên nhân chủ yếu nào? Trên cơ sở đó, em hãy rút ra những bài học kinh nghiệm cho công cuộc bảo vệ tổ quốc hiện nay.
Từ bài thơ Mây và sóng của nhà thơ ta go em rút ra bài học gì cho bản thân
I. PRONUNCIATION Exercise 1: Choose the word whose underlined part is pronounced differently from the others. 1. A. fertilizer B. disaster C. diversity D. environment 2. A. atmosphere B. ecosystem C. erosion D. enrol 3 A. image B. sewage C. manage D. engage 4. A. aquatic B. contamination C. catastrophe D. atmosphere Exercise 2: Choose the word whose stress pattern is different from that of the others. 1. A. disappear B. environment C. contaminate D. renewable 2. A. evaporate B. disaster C. poisonous D.diversity 3. A. environmentalist B. substainable C. urbanization D. biological 4. A. endangered B. habitat C. detergent D. extinction II. VOCABULARY AND GRAMMAR Choose the best answer which best fits each space in each sentence. 1 …………… can cause stress and psychological and health problems for humans such as increased heart rate and hearing damage. A. water pollution B. air pollution C. noise pollution D. soil pollution 2. Do you know how to do waste… ? A. separation B. division C. selection D. option 3. I wondered… the right thing. A. if I am doing B. was I doing C. am I doing D. whether I was doing 4. Julia said that she… there at noon. A. is going to be B. was going to be C. will be D. can be 5. Coastal cities often dump their… wastes into the sea. A. recycled B. untreated C. reused D. reduced 6. The rocks have… away over time. A. eroded B. evolved C. exhausted D. exposed 7. Animals are dying… far more often than you might think. A. from B. out C. for D. of 8. A……………energy system converts the energy found in sunlight, wind, falling water, waves, geothermal heat, or biomass. A. renewable B. non-renewable C. reusable D. released 9. used water, comes from factories and households. A. Sewage B. Emission C. Detergents D. Poison 10. The… is the rise in temperature caused by gases in the atmosphere. A. climate change B. greenhouse effect C. global warming D. deforestation III. WORD FORM Use the word given in capitals at the end of each line to form a word that fits in the space in the same line. There is an example at the beginning (0). An accurate (0) prediction of the weather used to (1) …………… be a case of intelligent estimates that (2) …………… turned out to be wrong. Now the (3) of weather forecasters has improved and there is a (4) …………… for them to be taken more seriously. (5) …………… in the weather caused by (6) …………… and global warming have worrying (7)…………… , though. The weather has become (8)…………… with cold days in summer and hot days in winter. These (9)… in the temperature act as a (10) from other world problems such as war but this makes them no less of concern. PREDICT PRIMARY CONSIST REPUTE TEND DISTURB POLLUTE IMPLICATE PREDICT VARY DISTRACT
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