Read the following passage and mark the letter A, B, C, or D to indicate the correct answer ACID DUST Calcite-containing dust particles blow into the air and combine with nitric acid in polluted air from factories to form an entirely new particle-calcium nitrate. These nitrates have optical and chemical properties that are completely different from those of the originally dry dust particles. Due to this, climate models need to be updated to reflect this chemistry. Calcite dust is common in arid areas such as Israel, where this past winter scientists collected particles for analysis.Working from a mountaintop, the team collected dust that had blown in from the northern shores of Egypt, Sinai, and southern Israel. The particles had combined with air containing pollutants that came from Cairo. They analyzed nearly 2,000 individual particles and observed the physical and chemical changes at the W.R Wiley Environmental Molecular Sciences Laboratory.An important change in the properties of the newly formed nitrate particles is that they absorb water and retain moisture. These particles can scatter and absorb sunlight-presenting climate modelers, who need to know where the energy is going, a new wild card to deal with. Other studies of dust samples from the Sahara and the Saudi Arabian coast and loess from China show that the higher the calcium in the mineral, the more reactive they are with nitric acid. In fact, once the particle is changed, it stays that way.
Câu 1: What is the main idea of the passage?
A. There is a new particle called calcium nitrate .
B. Factories are polluting the environment.
C. Climate models have to be updated because of the new particle calcium nitrate.
D. Calcium nitrate has chemical properties different from other dust particles.
Câu 2: Why do climate models need to be updated to reflect the chemistry of calcium nitrate?
A. The new particles can absorb water and retain moisture.
B. The new particles can scatter and absorb sunlight.
C. to stop acid dust
D. The new particles can absorb water, retain moisture , scatter and absorb sunlight.
Câu 3: Do the particles react with nitric acid?
A. No, but they continue to absorb the sun's energy.
B. No, and the particles do not change.
C. Yes, but the changes are temporary.
D. Yes, and the changes are permanent.
Câu 4: Which of the following may be a result of these particles?
A. The chance of an ice age is increased.
B. We may see more rainbows.
C. The greenhouses effects are increased.
D. We may see an increase in carbon dioxide.
Câu 5: Why does the passage begin with a description of the properties of calcium nitrate?
A. to give background information so the reader can understand the topic better
B. Because calcium nitrate is the main idea.
C. to show how elements combine to create calcium nitrate
D. to prove the existence of calcium nitrate
Câu 6: The word "those" in paragraph 1 refers to:
A. nitrates
B. properties
C. particles
D. models
Câu 7: In the scientists' research, where did the pollutants come from originally?
A. arid areas
B. the Saudi Coast
C. Cairo
D. the Sahara desert
Câu 8: It can be inferred that "retain" in the paragraph 3 is closet in meaning to:
A. hold
B. lose
C. increase
D. need
Câu 9: What is the purpose of the passage?
A. to convince the reader that calcium nitrate is bad
B. to inform the reader of a new problem in climate modeling
C. to show how calcium nitrate was created
D. to show where calcium nitrate was first discovered
Câu 10: In the third paragraph, what does the term "wild card" mean?
A. an unknown card in the card game
B. an unknown item in the scientists' calculation
C. a large amount of acid dust
D. none of the above
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