7th Std Science Term 3 Solution in English | Lesson.4 Chemistry in Daily Life

Lesson 4. Chemistry in Daily Life

Lesson 4. Chemistry in Daily Life

I . Choose the correct answer.

1.  A drug effective in the treatment of pneumonia, and bronchitis, is _________

1. a. Streptomycin
2. Chloramphenicol
3. Penicillin
4. Sulphaguanidine

Ans : Penicillin

2. Aspirin is ___________

1. Antibiotic
2. Antipyretic
3. Sedative
4. Psychedelic

Ans : Antipyretic

3.  __________ are that neutralize stomach acid.

1. Antacid
2. Antipyretic
3. Analgesic
4. Antihistanics

Ans : Antacid

4. The lowest temperature at which a substance catch the fire is called its ________

1. Boiling point
2. Melting point
3. Critical temperature
4. Ignition temperature.

Ans : Ignition temperature.

5. Which is the hottest part in the flame of candle _________

1. Blue
2. Yellow
3. Black
4. Way part

Ans : Blue

II. Fill in the blanks:

1. Penicillin was first discovered by _________

Ans : Alexander Fleming 

2. World ORS Day is _________

Ans : July 29

3. Combustion is a chemical reaction in which and substance react with _________

Ans : Oxygen

4. In the presence of water, the ignition temperature of paper is _________

Ans : Constant

5. Fire produced by oil cannot be controlled by _________

Ans :  Water

III. Match the following:

IV. True or False – If false give the correct answer:

1. Antibiotics does work for viruses like cold and

Ans : True

2. Analgesics are the substances that lower the temperature during fever.

Ans : False

3. All fuels form flame

Ans : False

4. Oxygen is necessary for combustion

Ans : True

5. Burning wood and coal causes pollution of air.

Ans : True

V. Analogy

1. Inner zone of flame : : ____________, outer zone of flame : : ____________

Ans : Black, Blue

2. Tincture: : ____________, cistamine : : ____________

Ans : Antiseptic, Disinfectant

VI. Very short answer

1. First viral disease detected in human being was :————— (Yellow fever / dengue fever)

Ans : Yellow fever

2. :—————, :————— , :————– are called green house gases (Fleming / lenis pastor)

Ans : Co₂, Methane. Chirorofluorocarbons

3. Name a substance which can be used as an antiseptic as well as disinfectant?

• Cralic
• Trumeric
• Alove vera

4. What are the main constituents of dettol?

Mixture of chloroxylenol and terpincol

5. Name the unit in which the calorific value of a fuel is expressed?

Calorific Value kJ / kg

6. How many types of combustion are there?

• Rapid combustion
• Spontaneous combustion
• Explosion

7. What are the essential requirements for producing fire?

• Fuel
• Heat
• Oxygen

VII. Short Answer Questions

1. Why should not medicines be taken without consulting doctors?

One should not take medicines without consulting doctors because if a wrong medicine is accidently eaten for a disease. it may not cure the disease but actually can have harmful side to the body

2. Why do antiseptics differ from disinfectants? Give one example of each.

3. What is ignition temperature?

The minimum temperature at which a substance catches fire and burns is called its ignition temperature.

4. If 4.5kg of fuel is completely burnt and amount of heat produced stands measured at 1, 80,000 KJ what is the calorific value.

VIII. Answer in Detail

1. Explain briefly about antibiotic and analgesic?

• Many micro organisms and plants synthesize chemicals which are toxic in nature to protect them from invading organisms.
• The biosynthesized chemicals isolated from the plants/micro organisms and used as medicines against infectious diseases. These substances were called as antibiotics.
• Ex: Chloramphenicols, tetracyclines, Penicillin derivatives, cephalosporin’s and their derivatives.
• The World’s first antibiotic penicillin was discovered by The world’s first antibiotic penicillin was discovered by Dr. Alexander Fleming.

2. Make labeled diagram of a candle flame

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