IELTS Practice Tests Plus Volume 2
- Published on: 15 Dec 2017
- Tests taken: 263,984
Answer Keys:
Part 1: Question 1 - 13
- 1 transportation
- 2 pharmaceuticals
- 3 manuscripts
- 4 sublimation
- 5 simple drying (techniques)
- 6 (freeze-drying) chamber
- 7 shelves
- 8 freezing coil
- 9 (refrigerator) compressor
- 10 enzymes
- 11 composition
- 12 overheating
- 13 high altitudes
Part 2: Question 14 - 27
- 14 NOT GIVEN
- 15 TRUE
- 16 TRUE
- 17 NOT GIVEN
- 18 NOT GIVEN
- 19 FALSE
- 20 woodland species
- 21 exotic flowers
- 22 (domestic) cats
- 23 81
- 24 26 C,E,G
- 27 C
Part 3: Question 28 - 40
- 28 iii
- 29 vi
- 30 ii
- 31 vii
- 32 viii
- 33 iv
- 34 C
- 35 A
- 36 B
- 37 C
- 38 B
- 39 A
- 40 B
Leaderboard:
| # | User | Score | Time | |
|---|---|---|---|---|
| 759385979 |
|
9.0 | 15:30 | |
| Nguyễn Lê Phước Duy |
|
9.0 | 17:23 | |
| Frosty Nhio |
|
9.0 | 20:16 | |
| 4 | Ekaterina Soboleva |
|
9.0 | 21:37 |
| 5 | Mahim Ezaz |
|
9.0 | 21:52 |
| 6 | sure rai |
|
9.0 | 25:32 |
| 7 | San Nguyen |
|
9.0 | 26:18 |
| 8 | Bùi Hữu Bảo |
|
9.0 | 30:53 |
| 9 | huongnamlun1910 |
|
9.0 | 31:54 |
| 10 | Isha Shah |
|
9.0 | 33:29 |
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Review & Explanations:
Questions 1-5
Complete the notes below.
Choose NO MORE THAN THREE WORDS from the passage for each answer.
Write your answers in boxes 1-5 on your answer sheet.
Uses of freeze-drying:
- food preservation
- easy 1 of food items
- long-term storage of 2 and biological samples
- preservation of precious 3
Freeze-drying
- is based on process of 4 is more efficient than 5
- 1 Answer: transportation
Keywords in Questions
Similar words in Passage
Q1. Uses of freeze-drying:
- food preservation
- _______ of food items
Removing this makes the food much lighter and therefore makes transportation less difficult.
+ The key word here is ‘freeze-drying’. The third paragraph talks about freeze-drying and it is mentioned that it makes transportation less difficult, which is a use.
+ Since the words “less difficult” has been paraphrased into “easy” in question, the correct answer is transportation.
- 2 Answer: pharmaceuticals
Keywords in Questions
Similar words in Passage
Q2. long-term storage of _______ and biological samples
The process is also used to preserve other sorts of material, such as pharmaceuticals.
Similarly, research scientists may use freeze-drying to preserve biological samples for long periods of time.
+ Moving on, in the fourth paragraph, it is written that this process is also used to preserve other materials like pharmaceuticals. To preserve means the same as long-term storage.
+ Since the words “biological samples” has been given, the correct answer is pharmaceuticals.
- 3 Answer: manuscripts
Keywords in Questions
Similar words in Passage
Q3. preservation of precious ________
Even valuable manuscripts that had been water damaged have been saved by using this process.
+ Again, on the same paragraph, it is mentioned that the process can be used to save valuable manuscripts even if they have been water damaged.
+ Hence, the correct answer is manuscripts.
- 4 Answer: sublimation
Keywords in Questions
Similar words in Passage
Q4. Freeze-drying is based on process of ______
This is possible because in freeze-drying, solid water - ice - is converted directly into water vapour, missing out the liquid phase entirely. This is called ‘ sublimation ’,
+ In the sixth paragraph, it is mentioned that in freeze-drying, the ice is converted directly to water vapour and that is called sublimation. This is a process that freeze-drying includes, hence, it is the correct answer. (sublimation)
- 5 Answer: simple drying (techniques)
Keywords in Questions
Similar words in Passage
Q5. Freeze-drying is more efficient than ______
Freeze-drying is different from simple drying because it is able to remove almost all the water from materials, whereas simple drying techniques can only remove 90-95%
+ The sixth paragraph also mentions that freeze-drying is different from simple drying as it is able to remove almost all the water from materials unlike simple drying techniques. This is certainly more efficient.
+ Hence, the correct answer is simple drying techniques.
Questions 6-9
Label the diagram below.
Choose NO MORE THAN TWO WORDS from the passage for each answer.
Write your answers in boxes 6-9 on your answer sheet.
A simplified freeze-drying machine
6
7
8
9
- 6 Answer: (freeze-drying) chamber
Keywords in Questions
Similar words in Passage
Q6. A simplified freeze-drying machine (to identify no. 6)
The material to be preserved is placed in a freeze-drying chamber which is connected to a freezing coil and refrigerator compressor .
+ Here, we are asked to identify the part numbered 6.
+ If you take a look at paragraph 7, it is written that “The material to be preserved is placed in a freeze-drying chamber which is connected to a freezing coil and refrigerator compressor.”
+ So, part no. 6 must be something that is connected to a coil, as seen in the figure.
+ Hence, the correct answer is (freeze-drying) chamber.
- 7 Answer: shelves
Keywords in Questions
Similar words in Passage
Q7. (to identify part no. 7)
______ with heating units
The heating units apply a small amount of heat to the shelves in the chamber, causing the ice to change phase.
+ In the seventh paragraph, it is mentioned that “The heating units apply a small amount of heat to the shelves in the chamber, causing the ice to change phase”. Hence, it seems that part with heating units is the shelves.
+ Therefore, the correct answer is shelves.
- 8 Answer: freezing coil
Keywords in Questions
Similar words in Passage
Q8. (to identify part no. 8)
Since the pressure in the chamber is so low, the ice turns directly into water vapour, which leaves the freeze-drying chamber, and flows past the freezing coil .
+ The seventh paragraph also mentions that the water vapour leaves the freeze-drying chamber and flows past the freezing coil. The part that is connected to the freeze-drying chamber from where the water vapor could pass is the freezing coil.
+ Hence, the answer is freezing coil.
- 9 Answer: (refrigerator) compressor
Keywords in Questions
Similar words in Passage
Q9. (to identify part no. 9)
The material to be preserved is placed in a freeze-drying chamber which is connected to a freezing coil and refrigerator compressor .
+ The seventh paragraph is again very important for this question as well. It is mentioned in the beginning of this paragraph that the freeze-drying chamber is connected to a freezing coil and refrigerator compressor. If you look at the picture, the next part that is connected past the freezing coil is the refrigerator compressor.
+ Thus, the correct answer is refrigerator compressor.
Questions 10-13
Complete the summary below.
Choose NO MORE THAN THREE WORDS AND/OR A NUMBER from the passage for each answer.
Write your answers in boxes 10-13 on your answer sheet.
- 10 Answer: enzymes
Keywords in Questions
Similar words in Passage
Q10. Freeze-drying prevents food from going bad by stopping the activity of microorganisms or
Similarly, the enzymes which occur naturally in food cannot cause ripening without water, so removing water from food will also stop the ripening process.
+ In the second paragraph, it is mentioned that enzymes cannot cause ripening by removing water from food. As it should be clear by now, removing water from food means freeze-drying and that to stop the activity of microorganisms is to stop the ripening process which is not possible without water.
+ So, the answer is enzymes.
- 11 Answer: composition
Keywords in Questions
Similar words in Passage
Q11. Its advantages are that the food tastes and feels the same as the original because both the … and structure are preserved.
In addition, the composition and structure of the material is not significantly changed, so materials can be revitalised without compromising the quality of the original.
+ If you look at the third last paragraph, it is mentioned that both the composition and structure of the material is not significantly changed that the original. It means that the composition and structure are preserved as the original.
+ Therefore, the answer should be composition.
- 12 Answer: overheating
Keywords in Questions
Similar words in Passage
Q12. The process is carried out slowly in order to ensure that… does not take place.
The process continues for many hours (even days) while the material gradually dries out. This time is necessary to avoid overheating , which might affect the structure of the material.
+ In the second last paragraph, it is mentioned that the process continues for many hours or days to avoid overheating. The time period of hours or days is very slowly and to avoid means to make sure something does not take place.
+ Therefore, the answer is overheating.
- 13 Answer: high altitudes
Keywords in Questions
Q13. The people of one ancient mountain civilisation were able to use this method of food preservation because the conditions needed were present at ..
The ancient Incas of Peru used mountain peaks along the Andes as natural food preservers. The extremely cold temperatures and low pressure at those high altitudes prevented food from spoiling in the same basic way as a modern freeze-drying machine and a freezer.
+ In the last paragraph, it is written that the Incas of Peru used mountain peaks along the Andes as natural food preservers due to low pressure and cold temperature at those high altitudes. It means those conditions were present at high altitude (Andes is a mountain range and Incas was a civilization as is mentioned)
+ Therefore, the answer is high altitudes.
READING PASSAGE 1
You should spend about 20 minutes on Questions 1 – 13, which are based on Reading Passage 1 below.
Astronaut ice cream, anyone?
Breeze-drying is a technique that can help to provide food for astronauts. But it also has other applications nearer home.
Freeze-drying is like suspended animation for food: you can store a freeze-dried meal for years, and then, when you’re finally ready to eat it. you can completely revitalise it with a little hot water. Even after several years, the original foodstuff will be virtually unchanged.
The technique basically involves completely removing the water from some material, such as food while leaving the rest of the material virtually intact. The main reason for doing this is either to preserve the food or to reduce its weight. Removing the water from food keeps it from spoiling, because the microorganisms such as bacteria that cause spoiling cannot survive without it. Similarly, the enzymes which occur naturally in food cannot cause ripening without water, so removing water from food will also stop the ripening process.
Freeze-drying significantly reduces the total weight of the food because most food is largely made up of water; for example, many fruits are more than 80 00% water. Removing this makes the food much lighter and therefore makes transportation less difficult. The military and camping-supply companies freeze-dry foods to make them easier for an individual to carry and NASA has also freeze-dried foods for the cramped quarters on board spacecraft.
The process is also used to preserve other sorts of material, such as pharmaceuticals. Chemists can greatly extend pharmaceutical shelf life by freeze-drying the material and storing it in a container free of oxygen and water. Similarly, research scientists may use freeze-drying to preserve biological samples for long periods of time. Even valuable manuscripts that had been water damaged have been saved by using this process.
Freeze-drying is different from simple drying because it is able to remove almost all the water from materials, whereas simple drying techniques can only remove 90-95%. This means that the damage caused by bacteria and enzymes can virtually be stopped rather than just slowed down. In addition, the composition and structure of the material is not significantly changed, so materials can be revitalised without compromising the quality of the original.
This is possible because in freeze-drying, solid water - ice - is converted directly into water vapour, missing out the liquid phase entirely. This is called ‘sublimation’, the shift from a solid directly into a gas. Just like evaporation, sublimation occurs when a molecule gains enough energy to break free from the molecules around it. Water will sublime from a solid (ice) to a gas (vapour) when the molecules have enough energy to break free but the conditions aren't right for a liquid to form. These conditions arc determined by heat and atmospheric pressure. When the temperature is above freezing point, so that ice can thaw, but the atmospheric pressure is too low for a liquid to form (below 0.06 atmospheres (ATM)) then it becomes a gas.
This is the principle on which a freeze-drying machine is based. The material to be preserved is placed in a freeze-drying chamber which is connected to a freezing coil and refrigerator compressor. When the chamber is sealed the compressor lowers the temperature inside it. I he material is frozen solid, which separates the water from everything around it on a molecular level, even though the water is still present. Next, a vacuum pump forces air out of the chamber, lowering the atmospheric pressure below to 0.06 ATM. The heating units apply a small amount of heat to the shelves in the chamber, causing the ice to change phase. Since the pressure in the chamber is so low, the ice turns directly into water vapour, which leaves the freeze-drying chamber, and flows past the freezing coil. The water vapour condenses onto the freezing coil in the form of solid ice, in the same way that water condenses as frost on a cold day.
The process continues for many hours (even days) while the material gradually dries out. This time is necessary to avoid overheating, which might affect the structure of the material. Once it has dried sufficiently, it is sealed in a moisture-free package. As long as the package is secure, the material can sit on a shelf for years and years without degrading, until it is restored to its original form with a little hot water. If everything works correctly, the material will go through the entire process almost completely unscathed.
In fact, freeze-drying, as a general concept, is not new but has been around for centuries. The ancient Incas of Peru used mountain peaks along the Andes as natural food preservers. The extremely cold temperatures and low pressure at those high altitudes prevented food from spoiling in the same basic way as a modern freeze-drying machine and a freezer.
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