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1) What is thermoplastic & thermo setting plastic.
3) Write 10 lines on the usefulness of micro organisms in our lives.
4) What precautions must be taken while taking antibiotics?
5) Explain why plastic containers are favored for storing food.
6) Can you store lemon pickle in a aluminum utensil? Explain.
7) What are the advantages of using CNG & LPG as fuel.
8) Describe Charactertics and uses of coke.
9) Explain the process of formation of petroleum.
10) What are the causes and consequences of deforestation?
11) How can you contribute to the maintenance of green wealth of your locality?
Make list of action to be taken by you.
12) Explain how Co2 is able to control fires?
13) What are the different ways in which water get contaminated ?
14) Explain the differences between pure air and polluted air.
15) Describe the "Green house affect". In your own words.
16) What is nuclear membrane?
17) What is Sexual reproduction?
18) What is a preservative?
19) What is nitrogen fixation?
20) What is yeast?
21) What is Rayon?
22) What is nylon?
23) What is artificial silk?
24) What is petro chemical?
24) What is acrylic?
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Answers
Answer:
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Answer:
1.In contrast to thermoplastics, thermosets (alternately known as thermosetting plastics or thermosetting polymers) are materials which remain in a permanent solid state after being cured one time. ... Common examples of thermoset plastics and polymers include epoxy, silicone, polyurethane and phenolic.
3.(i) Microorganisms help us in food sector. They are used for curdling of milk, preparation of bread, cake, etc. ... (vii) Microorganisms are used to prepare vaccines for various diseases. (viii) They are useful for agriculture sector, as they enhance the fertility of soil by fixing nitrogen
4.Antibiotics should be taken only on the advice of a qualified doctor. One must finish the course prescribed by the doctor. Antibiotics must be avoided when not needed or in wrong doses
5.Plastic containers are favored for storing food because plastic is non-reactive and will not react with the ingredients of the food items. Plastic is more easily accessible and is economically friendly to all people. Plastic containers are heavily used in the packaging industry.
6.The lemon pickle contains acids. Metals like aluminum readily react with acid to liberate hydrogen gas. This can lead to spoiling of the pickle.
7.The advantages of using CNG and LPG as fuels are as follows: They both are cleanest burning fuels of all fossil fuels. They are less polluting, non-corrosive. They can be sent through pipes easily.
8.The characteristics of coke are as follows: It is a tough, porous and black substance. It is an almost pure form of carbon. It gives little or no smoke.
The uses of coke are as follows:
It was used for domestic heating in the past.
It is used for the extraction of metals.
It is used in the manufacture of steel.
9.A fossil fuel, petroleum is formed when large quantities of dead organisms, mostly zooplankton and algae, are buried underneath sedimentary rock and subjected to both intense heat and pressure. Petroleum has mostly been recovered by oil drilling.
10.The loss of trees and other vegetation can cause climate change, desertification, soil erosion, fewer crops, flooding, increased greenhouse gases in the atmosphere, and a host of problems for indigenous people.
11.We can contribute to the maintenance of green wealth: by taking following actions:
* By taking care of the plants and trees growing in our locality.
* By planting more and more trees.
* By encouraging awareness among the people in the locality about the importance of growing trees.
* By watering them regularly.
12.Carbon dioxide is heavier than oxygen, covers the fire like a blanket. Since the contact between the fuel and oxygen is cut off, the fire is controlled. The added advantage of CO2 is that in most cases it does not harm the electrical equipment.
13.Water gets contaminated by following:
Untreated sewage.
Practice of bathing and washing near a water body.
Practice of cremating the dead bodies near river banks.
Oil spill.
Throwing chemical waste into waters.
Dumping agricultural waste into water.
14. Pure air is free from germs and harmful gases. It contains 78% nitrogen, 21% oxygen and small amount of other gases and dust particles. Polluted air contains harmful gases and unwanted substances.
15.The greenhouse effect is a natural process that warms the Earth's surface. When the Sun's energy reaches the Earth's atmosphere, some of it is reflected back to space and the rest is absorbed and re-radiated by greenhouse gases. ... The absorbed energy warms the atmosphere and the surface of the Earth.
16A nuclear membrane is a double membrane that encloses the cell nucleus. It serves to separate the chromosomes from the rest of the cell. The nuclear membrane includes an array of small holes or pores that permit the passage of certain materials, such as nucleic acids and proteins, between the nucleus and cytoplasm
17.Sexual reproduction is a type of reproduction that involves a complex life cycle in which a gamete (such as a sperm or egg cell) with a single set of chromosomes (haploid) combines with another to produce an organism composed of cells with two sets of chromosomes (diploid).
18.A preservative is a substance or a chemical that is added to products such as food products, beverages, pharmaceutical drugs, paints, biological samples, cosmetics, wood, and many other products to prevent decomposition by microbial growth or by undesirable chemical changes.
19.Nitrogen fixation is a chemical process by which molecular nitrogen in the air is converted into ammonia or related nitrogenous compounds in soil or aquatic systems. Atmospheric nitrogen is molecular dinitrogen, a relatively nonreactive molecule that is metabolically useless to all but a few microorganisms