Term 3 · Class 7 Science · Chapter 4

Samacheer Class 7 Science - Chemistry in Daily Life

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Chapter-wise textbook exercise answers for Chemistry in Daily Life with validation-aware solutions.

Answers marked verified were checked during generation against the chapter context and source question text.
Sections in this chapter
I. Choose the correct answers : 5II. Fill in the blanks : 1III. True or False – If False, give the correct answer : 5IV. Match the following : 1V. Analogy: 1VI. Very short answer : 7VII. Short Answer Questions: 4VIII. Answer in Detail: 2IX. Picture based question 1Activity 1
Your Progress - Chapter 40% complete
1I. Choose the correct answers :5 questions
Q.1A drug effective in the treatment of pneumonia, and bronchitis, is ______v
  1. A. Streptomycin
  2. B. Chloramphenicol
  3. C. Penicillin
  4. D. Sulphaguanidine
Answer:

(c) Penicillin

Q.2Aspirin is ______v
  1. A. Antibiotic
  2. B. Antipyretic
  3. C. Sedative
  4. D. Psychedelic
Answer:

(b) Antipyretic

Q.3______ are that neutralize stomach acid.v
  1. A. Antacid
  2. B. Antipyretic
  3. C. Analgesic
  4. D. Antihistanics
Answer:

(a) Antacid

Q.4The lowest temperature at which a substance catch the fire is called its ______v
  1. A. Boiling point
  2. B. Melting point
  3. C. Critical temperature
  4. D. Ignition temperature
Answer:

(d) Ignition temperature

Q.5Which is the hottest part in the flame of candle ______v
  1. A. Blue
  2. B. Yellow
  3. C. Black
  4. D. Way part
Answer:

(a) Blue

2II. Fill in the blanks :1 questions
Q.G1Penicillin was first discovered by ______ World ORS Day is ______ Combustion is a chemical reaction in which and substance react with ______ In the presence of water, the ignition temperature of paper is ______ Fire produced by oil cannot be controlled by ______v
Answer:

Alexander Fleming
July 29
oxidizing agent
not reached
water

3III. True or False – If False, give the correct answer :5 questions
Q.1Antibiotics does work for viruses like cold andv
Answer:

(False)
Correct statement: Antibiotics does not work for viruses like cold and flu

Q.2Analgesics are the substances that lower the temperature during fever.v
Answer:

(False)
Correct statement : Antipyretic are the substances that lower the temperature during fever.

Q.3All fuels form flame.v
Answer:

(False)
Correct statement: All fuels do not form flame.

Q.4Oxygen is necessary for combustion.v
Answer:

True

Q.5Burning wood and coal causes pollution of air.v
Answer:

True

4IV. Match the following :1 questions
Q.11. Antipyretic Reduce pain 2. Analgesic Reduce body temperature 3. Antacid Spontaneous combustion 4. Phosphorus ORS Solution 5. Carbon – di – oxide Leads to respiratory problemv
Answer:

1. Antipyretic
Reduce body temperature
2. Analgesic
Reduce pain
3. Antacid
ORS Solution
4. Phosphorus
Spontaneous combustion
5. Carbon – di – oxide
Leads to respiratory problem.

5V. Analogy:1 questions
Q.2Tincture:: ______, Histamine : : _______v
Answer:

Antiseptic, Chemical messenger

6VI. Very short answer :7 questions
Q.1First viral disease detected in human being was : _____ (Yellow fever / dengue fever)v
Answer:

Yellow fever.

Q.2______,:_______,:_______ are called green house gasesv
Answer:

CO 2 , Methane, Chlorofluorocarbons

Q.3Name a substance which can be used as an antiseptic as well as disinfectant.v
Answer:

Garlic, Turmeric, Aloe vera.

Q.4What are the main constituents of dettol?v
Answer:

Mixture of chloroxylenol and terpincol

Q.5Name the unit in which the calorific value of a fuel is expressed.v
Answer:

KJ/Kg.

Q.6How many types of combustion are there?v
Answer:

Rapid combustion
Spontaneous combustion
Explosion

Q.7What are the essential requirements for producing fire?v
Answer:

Fuel, Heat and Oxygen.

7VII. Short Answer Questions:4 questions
Q.1Why should not medicines be taken without consulting doctors?v
Answer:

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 effects to the body.

Q.2Why do antiseptics differ from disinfectants? Give one example of each.v
Answer:

Difference between Antiseptic and Disinfectants
Antiseptic
Disinfectants
1.
All antiseptic are disinfectants
1. All disinfectants are not antiseptic
2.
It can be applied on the live tissue
2. It can be apply on in animate object
3.
E.g. skin / Mucous
3. E.g. Surface, lab working tables, floor.

Q.3What is ignition temperature?v
Answer:

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

Q.4If 4.5kg of fuel is completely burnt and amount of heat produced stands measured at 1,80,000 KJ. What is the calorific value?v
Answer:

Amount of fuel = 4.5 kg
Heat produced = 1,80,000 kj
Calorific value = ?∴ Calorific value = 40,000 kj/kg

8VIII. Answer in Detail:2 questions
Q.1Explain briefly about antibiotic and analgesic.v
Answer:

Many micro organisms and plants synthesize chemicals which are toxic in nature to protect them from invading organisms.
Those biosynthesized chemicals can be isolated from the plants/micro organisms and was 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 Dr. Alexander Fleming.
Analgesics:
Analgesics or pain killers that react like the pain-suppressing chemicals released by the body.
They suppress the feeling of ‘pain.
This analgesics drug selectively relieves pain by acting either in CNS (Central Nerves System) or on peripheral pain mechanism, without significantly altering consciousness.

Q.2Make labeled diagram of a candle flame.v
Answer:

9IX. Picture based question1 questions
Q.1Arul and Aakash were doing an experiment in which water was to be heated in a beaker. Arul kept the beaker near the wick in the yellow part of candle flame. Aakash kept the beaker in the outer most part to the flame. Whose water will get heated in a shorter time? v
Answer:

The water heated by Akash will get heated in a shorter time because he kept his beaker near the hottest (non- luminous) zone of the flame. But Arul kept the beaker in the luminous zone which is moderately hot. So, it will take longer time.

10Activity1 questions
Q.1What happens when you add with these chemicals? Sugar + Potassium permanganate + Glycerin v
Answer:

After adding sugar, potassium permanganate and glycerin to the dish, immediately step back because spark and solid potassium permanganate will be expelled from the dish.
When potassium permanganate mixes with glycerin, a redox reaction starts. This reaction starts out really slow, but produces a lot of heat, so it will start to speed up bit by bit. As the potassium permanganate oxidises the sugar, it will speed up more and more until it finally starts to smoke and after that it will ignite.