Samacheer Kalvi 9th Science Book Back Answers Chapter 24

Samacheer Kalvi 9th Science Book Back Question and Answers:

Samacheer Kalvi 9th Standard Science Book Back 1 Mark and 2 Mark Question & Answers PDF uploaded and available below. Class 9 New Syllabus 2022 to 2023 Book Back Questions & Answers/solutions available for both English and Tamil Medium. Class 9 std Science Book Term 3 Chapter 6 – Applied Chemistry Answers/Solutions Guide are uploaded on this page. In the new 9th Science syllabus Term 1, Term 2 and Term 3 are combined into a single book. The 9th standard Science Book consists of 27 Units. All 27 chapters of Term 1st, 2nd, 3rd Science Book Back One, and Two Mark Solutions are given below.

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9th Science Book Back Term 3 Chapter 6 Solutions Guide PDF:

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9th Science Term 3 Chapter – 6

Applied Chemistry – Book Back Answers


I. Choose the correct answer:

1. One Nanometre is
a) 10-7metre   b) 10-8metre
c) 10-6metre   d) 10-9metre

2. The antibiotic penicillin is obtained from
a) plant      b) microorganisms
c) animal   d) sunlight

3. 1% solution of Iodoform is used as
a) antipyretic      b)anti malarial
c) antiseptic    d) antacid

4. The cathode of an electrochemical reaction involves
a) oxidation           b) reduction
c) neutralization   d) catenation

5. The age of a dead animal can be determined by using an isotope of
a) carbon           b) iodine
c) phosphorous   d) oxygen

6. Which of the following does not contain natural dyes?
a) potato   b) beetroot
c) carrot       d) turmeric

7. The type of food protects us from deficiency diseases.
a) carbohydrates   b) vitamins
c) proteins              d) fats

8. Radiochemistry deals with
a) oxidants       b) batteries
c) isotopes    d) nanoparticles

9. The groups responsible for the colour of an organic compound are called
a) isotopes       b) auxochrome
c) chromogen  d) chromophore

10. Chlorinated hydrocarbons are used as
a) fertilizers              b) pesticides
c) food colourants   d) preservatives

II. Fill in the blanks:

1. Galvanic cell is an electrochemical cell which converts electrical energy into chemical change (reaction).
2. Painkiller drugs are called Analgesics.
3. Aspirin is an Antipyretic.
4. Nitrogen, Phosphorus and Potassium are macronutrients required for plant growth.
5. Ninhydrin is a chemical used in finger print analysis.

III. Match the following:

1. Antipyretics                  a) Large surface area
2. Corrosion prevention b) Iodine – 131
3. Hyperthyroidism         c) Fever
4. Nanoparticle                 d) Cancer cell identification
5. Nanorobotics                 e) Electroplating
Ans: 1- c; 2- e; 3-b; 4-a; 5-d

IV. Short Questions & Answers:

1. What is Chemotherapy?
Chemotherapy is the treatment of certain diseases by destroying the invading organism without damaging the cells of the host, by the use of certain organic compounds.

2. What is called Anaesthetics? How are they classified?
The drugs which cause loss of sensation are called anaesthetics. They are given to patients when they undergo surgery.
Anaesthetics can be classified into two types namely:
1. General Anaesthetics; 2. Local Anaesthetics.
General anaesthetics bring about loss of all modalities of sensation, particularly pain along with reversible loss of consciousness. The patient loses consciousness for specific period of time. Local anaesthetics prevent the pain sensation in localized area without affecting the degree of consciousness.

3. What is the need for chemical fertilizers in crop fields?
Fertilizers are chemical compounds added to crop field for supplying essential micro and macro nutrients required for crop growth. Ammonium nitrate, calcium phosphate, urea, NPK (Nitrogen, Phosphorus and potassium) etc., are some of the fertilizers. Depending on the nature of soil these fertilizers are used singly or as minutes.

4. What is Forensic Chemistry related to?
Forensic chemistry applies scientific principles, techniques and methods to the investigation of crime. It is related to (i) Finger print analysis (ii) Biometrics (iii) Alcohol test and (iv) Forensic Toxicology.

5. Batteries that are used in mobile phone can be recharges. Likewise, can you recharge the batteries used in watches? Justify your answer.
In watches alkaline batteries are used. It is a non rechargeable battery. Recharging this battery can result in rupture and leakage.

6. Sudha met with a fire accident. What kind of drug(s), must she take?
Sudha met with a fire accident she must take drugs like Bacitracin and Silver sulfadiazine.

7. The soil pH of a crop land is 5. What kind of fertilizers should be used in that land?
pH value 5 shows that the soil is acidic. To neutralize it we should add pulverized limestone. Limestone acts as a soil acid neutralizer.

8. Name various food additives and explain their factions.

Types of additive Function of the additive Example
Preservatives They protect food from spoilage by microorganisms in storage. Vinegar, Sodium benzoate, benzoic acid, sodium nitrite
Colourants They give pleasant colours to food. Caroteniods,  Anthocyanin, Curcumin
Artificial Sweetners They add sweet taste to food Saccharin, Cyclamate
Flavor enhancers They are used to enhance the flavor of food items. Monosodium  glutamate, calcium diglutamate
Antioxidants They prevent the oxidation of food. They protect us against cardiovascular disease Vitamin C, Vitamin E, Carotene

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