100% FREE ACCESS8th Standard Syllabus & Materials
8th Standard
TN 8th Tamil இயல் 3 - கல்வி கரையில - வினைமுற்று Important Questions And Answers Study Material - QB365 Set A
NEW8th Standard
TN 8th Tamil இயல் 2 - ஈடில்லா இயற்கை - மயங்கொலிகள் Important Questions And Answers Study Material - QB365 Set A
NEW8th Standard
TN 8th Tamil இயல் 2 - ஈடில்லா இயற்கை -பட்டமரம் Important Questions And Answers Study Material - QB365 Set A
NEW8th Standard
TN 8th Tamil இயல் 2 - ஈடில்லா இயற்கை - இயற்கையை போற்றுவோம் Important Questions And Answers Study Material - QB365 Set A
NEW8th Standard
TN 8th Tamil இயல் 1 - தமிழ் இன்பம் - ஆழிக்கு இணை Important Questions And Answers Study Material - QB365 Set A
NEW8th Standard
TN 8th Tamil இயல் 2-ஈடில்லா இயற்கை - திருக்குறள் Important Questions And Answers Study Material - QB365 Set A
Published on: 01/10/2019
Term 1 Matter
Download Tamil Nadu 8th Standard Science question papers, model tests, one-mark questions, important questions, and public exam papers in PDF format. Free study materials and answer keys for TN State Board students.
Questions + Answers key
Take MCQ Science Test1.
Give some uses of metalloids
2.
What are organic compounds? Give example.
3.
What are inorganic compounds? Give example.
4.
What are Semi conductors? Give example.
5.
What is a compound? Give example.
6.
Write the chemical names constituents and uses of some compounds.
7.
Write the uses of some non-metals
8.
write the uses of some metals
9.
Explain the physical properties of non metals
10.
Explain the physical properties of metals.
1.
(i) Silicon is used in electronic devices.
(ii) Boron is used in fire works.
(iii) Boron is used as a fuel for ignition in rocket
2.
(i) Compounds obtained from living sources like plants, animals etc. are called as organic compounds.
(ii) (ex) Protein, Carbohydrates
3.
(i) Compounds obtained from non living sources like rock, minerals etc. are called as inorganic compounds.
(ii) (ex) Chalk, baking powder
4.
(i) Metalloids which can act as electrical conductors under specific conditions are called as semi conductors.
(ii) (ex) Silicon, Germanium.
5.
(i) The molecule of a substance that contains two or more atoms of different elements combined together in a definite ratio is called as a compound.
(ii) (ex) CO2, H2O
6.
Uses of Compounds
Let us tabulate some compounds and their constituents that we use in our daily lif
| Common Name | Chemical Name | Constituents | Uses |
| Water | Hydrogen Oxide | Hydrogen and oxygen | For drinking and as solvent |
| Table salt | Sodium chloride | Sodium and chlorine | Essential component of our daily diet preservative for meat and fish |
| Sugar | Sucrose | Carbon, hydrogen and oxygen | Preparation of sweets, toffees and fruit juices |
| Baking soda | Sodium bicarbonate | Sodium, hydrogen, carbon and oxygen | Fire extinguisher preparation of baking powder and preparation of cakes and bread. |
| Washing soda | Sodium carbonate | Sodium, carbon and oxygen | As cleaning agent in soap and softening of hardwater. |
| Bleaching powder | Calcium oxychloride | Calcium, oxygen and chlorine | As bleaching agent, disinfectant and sterilisation of drinking water |
| Quick lime | Calcium oxide | Calcium and oxygen | Manufacture of cement and glass. |
| Lime stone | Calcium carbonate | Calcium, carbon and oxygen | Preparation of chalk pieces |
7.
| S.No | Non-Metals | Uses |
|---|---|---|
| 1. | Diamond (a form of carbon) | jewels, cutting and grinding equipments. |
| 2. | Graphite (a form of carbon) | pencil lead, lubricant |
| 3. | Sulphur | gun powder, vulcanisation of rubber |
| 4. | Phosphorous | Matches, rat poison |
| 5. | Nitrogen | Ammonia, fertilizer |
| 6. | Chlorine | bleaching agent, sterilization of water |
| 7. | Hydrogen | rocket fuel, cutting and welding reducing agent. |
8.
| S.No | Metals | Uses |
|---|---|---|
| 1 | Iron | for making bridges, engine parts iron sheet and bars |
| 2 | Copper | electrical wires, coins, statues |
| 3 | Silver and gold | Jewels, decorative purposes, photo graphy |
| 4 | Mercury | thermometers and barometers |
| 5 | Aluminium | electrical wires, cables,aerospace industries |
| 6 | Lead | automobile batteries, X-ray machines |
9.
| S.No | Property | Non-metals | Exceptions |
|---|---|---|---|
| 1 | Physical State | Solids, liquids or gases | - |
| 2 | Hardness | not hard | diamond |
| 3 | Lustre | not shiny | graphite, iodine |
| 4 | 4 Density | Soft, have low density | diamond |
| 5 | Melting point & boiling point | low | Carbon,Silicon boron |
| 6. | Tensile strength | do not have tensile strength | Carbon fibre |
| 7 | Malleability | Non-malleable | - |
| 8 | Ductility | Non-ductile | Carbon fibre |
| 9 | .Conductivity | bad conductors | graphite |
| 10 | Sonorous | do not give ringing | - |
10.
| S.No | Property | Metals | Exceptions |
|---|---|---|---|
| 1 | Physical State | Solids at room tempe | Mercury, Cesium Rubidiu Francium, Gallium liquids at or above room tempe |
| 2 | Hardness | Hard, Osmium can scratch glass | Sodium and potassium are soft |
| 3 | Lustre | Shiny | Calcium |
| 4 | Density | High | Sodium and potassium |
| 5 | Melting point & boiling point | High | Sodium potassium mercUT¥, gallium |
| 6 | Tensile strength | High | Zinc |
| 7 | Malleability | Malleable | - |
| 8 | Ductility | Ductile | - |
| 9 | Conductivity | Good conductors | Bismuth, tungsten |
| 10 | Sonorous | Governing sound | - |
8th Standard Syllabus & Materials
8th Standard
TN 8th Tamil இயல் 3 - கல்வி கரையில - பாடறிந்து ஒழுகுதல் Important Questions And Answers Study Material - QB365 Set A
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TN 8th Tamil இயல் 2 - ஈடில்லா இயற்கை - தமிழர் மருத்துவம் ( நேர்காணல்) Important Questions And Answers Study Material - QB365 Set A
Tamilnadu Stateboard 8th Standard Subjects
Tamilnadu Stateboard Standards
