(iii) in oxy-hydrogen flame for cutting and welding metals. State whether a displacement reaction will occur if the following are mixed. The heat evolved is not sufficient for the hydrogen to catch fire.Ca(s) + 2H2O(l) → Ca(OH)2(aq) + H2(g)Calcium starts floating because the bubbles of hydrogen gas formed stick to the surface of the metal. If you are an engineer constructing a multi storey building, which alloy would you be extensively using and why? (c) Hard substances that conduct heat and electricity and have a characteristic lustre or shine. Metallurgical process can be divided into following steps : Reduction of metal compound to get free metal. Platinum, gold and silver are used for making jewellery as they do not tarnish. NCERT Solutions; _Class 6 ; _Class 7; _Class 8; _Class 9; _Class 10; _Class 11; _Class 12; Revision Notes; _Class 6; _Class 7; _Class 8; _Class 9; _Class 10; _Class 11; _Class 12; Important Questions; _Class 6; _Class 7; _Class 8; _Class 9; _Class 10; _Class 11; _Class 12; Download App; Watch Videos; Download App. When it is red hot, it reacts with steam. German silver has (copper/silver) as major constituent. Unlike gold, silver is present in many naturally occurring minerals. An iron knife kept dipped in blue copper sulphate solution changes to light green because iron replaces copper from copper sulphate and forms iron sulphate. To avoid this they are stored in kerosene. Which of the following countries do not have huge reserves of Petroleum and natural gas? Which one of the following best defines a rock which contains enough mineral to make it economically viable for mining, 11. When iron nails are placed in copper sulphate solution, iron sulphate and copper are formed. [DAV2008]. (But take care that you don’t hurt yourself in the process). iron sulphate and coppere. Metals aremalleable and ductile in nature whereas non-metals are neither malleable nor ductile; they are brittle. 3. Minerals are solid natural substances that are made of the same material all the way through. (ii) Electroplating: Tin is electroplated on iron to make food containers commonly called tin cans. Describe an experiment to show the conditions necessary for rusting of iron. GOLDEN, Colo., Oct. 31, 2018 (GLOBE NEWSWIRE) -- Golden Minerals Company (“Golden Minerals”, “Golden” or “the Company”) (NYSE American and TSX: AUMN) is pleased to announce high-grade silver-gold assays from its Yoquivo project located in Chihuahua, Mexico. It can only be stored in a liquid hydrocarbon like mineral oil or kerosene oil. To understand rocks you need to become familiar with minerals and how they are identified. What is the process in which minerals lying near the surface are dug? What is the percentage’of gold in the ornaments ? It is used in the manufacture of sulphuric acid. THE DEFINITION OF ORGANIC: Organic chemistry is the study of those substances containing carbon in combination with hydrogen (H), and a few other non metals, namely oxygen (O), nitrogen (N), sulfur (S) and the halogens (F 2 , Cl 2 , Br 2 , and I 2 ). Ans: This is because it is very expensive. Ans: No, a wire cannot be drawn out of wood because wood is not a metal, thus it does not have ductility property. Also write the equation of the reaction. Suppose copper was high up in the reactivity series? Why not? Beaker A: Copper sulphate (CuSO4) + Zinc granule (Zn), Beaker B: Copper sulphate (CuSO4) + Iron nail (Fe). Mineral Class: Gold: Gold AUCTIONS: ALL ABOUT: Gold is the most malleable and ductile metal, which makes it very easy to work with. The mineral fuels like coal and petroleum are also non-metallic minerals. Hit hard the aluminium wire also. 1. 2. 3. Name the country with the largest reserve of iron ore. 2. Applying grease or oil on the surface has a similar effect. A native element and precious metal, gold has long been prized for its beauty, resistance to chemical attack and workability. Ans: It is done by passing an electric current through sulphuric acid using aluminium rod as anode. Minerals are inexhaustible. Your email address will not be published. Give reason for your answer. Strong generalities exist in this class. Pure Gold lacks resistance to pressure and easily bends. 2. some other metal such as gold, silver, copper or lead. It never tarnishes, and is unaffected by most chemicals. MCQ Questions for Class 10 Science: Ch 3 Metals and Non-Metals. 5. (a) A metal which floats on water, reacts with it and forms an alkali. Sulphur is the main constituent of skin ointments. (Iodine/bromine) has antiseptic properties. Thus, it will replace copper.Zn + CuSO4 –> ZnSO4 + Cu, (b) Copper sulphate and Iron: A displacement reaction will occur because iron is placed above copper. A. carbonates B. native elements C. halides D. sulfates and sulfides. The solid earth is made of rocks, which are made of minerals. What happen as a result of the reaction, Answer: Carbon is a non metal. MCQ Questions for Class 8 Geography: Ch 3 Mineral and Power Resource. (i) Sodium reacts vigorously with water, giving off a lot of heat. We can’t use pure gold to make jewellery. Making pencil leads: – Graphite 6. 2. Silver tarnishes black with a surface layer of acanthite (silver sulphide), especially when placed in proximity to sulphurous compounds. Gold and silver are usually recovered from the electrolysis sludge, and help the economics of the process. What are noble metals? 2. making surgical instruments d. making bodies of aircraftse. Question 1. Platinum, gold and silver are used for making jewellery as they do not tarnish. Log in for more information. (iii) Metals react with dilute acid, like dilute HCl to give a metal salt and H2 gas.2Na + 2HCl → 2NaCl + H2Hydrogen gas is not evolved when a metal reacts with nitric acid (HNO3) . As HNO3 is a strong oxidizing agent, it oxidizes the H2 to water and itself gets reduced to oxide of nitrogen (N2O, NO, NO2).Magnesium and Manganese react with very dil.HNO3 to give H2 gas.Mg(s) + 2HNO3 (aq) → Mg(NO3)2 + H2 ; Mn (s) + 2HNO3(aq) → Mn(NO3)2 + H2. 7. Mineral is a substance that occurs naturally and has definite chemical composition. 2K(s) + 2H2O(l) → 2KOH(aq) + H2(g) + heat energy. 2Cu + O2 → 2CuO; 4Al + 3O2 → 2Al2O3. Noble gases are found in (free state/compound forms). So, it can be used to wrap food items. iron sulphate and zinc, Ans:(a) Copper sulphate and Zinc: A displacement reaction will occur between copper sulphate and zinc because zinc is placed above copper in the reactivity series. 15. But the tablets were not hard and did not look like iron at all. Noble gases are found in (free state/compound forms). False vi. 14. Mineral - Mineral - Classification of minerals: Since the middle of the 19th century, minerals have been classified on the basis of their chemical composition. Question 1.Which of the following properties is generally not shown by metals? 9. Thus, it will replace iron.Zn + FeSO4 —> ZnSO4 + Fe. (ii) What is an ore? True v. Gold, silver and copper are ferrous mineral. 4. This reaction forms a gaseous mixture of carbon monoxide and hydrogen, called water gas. (d) A metal that reacts with oxygen without burning. The metallic oxide formed would be acidic or basic in nature ? 6. Ans: Aqua regia, (Latin for ‘royal water’) is a mixture of concentrated hydrochloric acid and concentrated nitric acid in the ratio of 3:1. 1. Potassium after combustion will form (acidic oxide/basic oxide). It forms complete series of solid solu­ tions with silver, copper, nickel, palladium, and platinum. 4. The native … However, its reactions with oxygen and water seem to indicate that it is less reactive than iron. Ans: This is because silver and gold are less reactive than hydrogen. 7. The material, generally used is(a) sulphur(b) graphite(c) PVC(d) none of theseAnswer:(c), Question 16.Which of the following non-metals is a liquid? They are:(a) Painting or applying oil: Painting the surface of the metal after cleaning it thoroughly is the most common method which keeps air away. Could you store 500 ml Zinc sulphate solution in an aluminum vessel overnight? Which of the metals become black in the presence of hydrogen sulphide ? Filled in gas balloon: – Helium 10. making accurate laboratory balances f. making bodies of ships, Ans. They are created with the help of natural processes and no human inte… Mg + H2O ——>MgO + H2 (iii) Zinc reacts only with steam.Zn + H2O —> ZnO + H2 ↑. Required fields are marked *. Boil it for one minute to remove any dissolved air. vii. Ans: .Bells are made of metals and not from wood because metals are sonorous but wood is not. Thus, it will not replace zinc. The Sulfide Class minerals comprise an economically important class of minerals. This is why we do not store Zinc sulphate solution in an aluminum vessel overnight. Most major ores of important metals such as copper, lead and silver are sulfides. CBSE Previous Year Question Paper for Class 10, CBSE Previous Year Question Paper for Class 12. It is probably the oldest precious metal known to humans. Aluminium foils are used to wrap food items. (c) It forms useful alloys. True ii. This happens because iron is more reactive than copper. Gold and silver atoms possess equal 1.44 angstrom atomic radii. Mineral and Power Resources. Why sodium and potassium stored in kerosene? Which of the metals become black in the presence of hydrogen sulphide ? (b) It is also used to make heating utensils, car radiators and calorimeters. 1 Answer/Comment. Ans: Different methods are used for preventing corrosion of metals. Record your observations in Table 4.1. NCERT Solutions Class 10 Science (Physics,Chemistry, Biology). Gold-Silver Series and Palladium-Silver Series. Write the equation also. Making electric wire: – copper and aluminium 4. 4. There chapter wise Practice Questions with complete solutions are available for download in myCBSEguide website and mobile app. 16. Making foil for wrapping food: – Aluminium5. (c) A metal which is used for galvanising iron. Silver is used in jewelry, tableware, coins, scientific equipment and in photographic processes. The Gold Group is composed of metallic elements that have the same crystal structure as gold. Which is one of the deepest gold mine of the world? They occur free in nature . (a) Amalgam(b) Brass(c) Bronze(d) SteelAnswer:(d), Question 10.Which of the following is purest form of carbon? Many types of minerals and rocks exist on Earth. Ans: Musical instrument and bell are made up of metal because metal produce ringing sound when stuck by something. Give the names and composition of alloys that are used for the following. It is one of the few reagents that is able to dissolve gold and platinum. Try to hit hard. Brass is an alloy of copper and zinc, in proportions which can be varied to achieve varying mechanical and electrical properties. It is used as a catalyst in the manufacture of sulphuric and nitric acid. Some examples of minerals are given below, pick out the one that is not a metallic mineral. Ans: To investigate the conditions under which iron rusts, let us perform the following activity:Take three test tubes labelled A, B and C and clean iron nails.In test tube A, put a few lumps of anhydrous calcium chloride (a good drying agent which absorbs water vapour from the atmosphere). Then repeat the same kind of treatment on the coal piece and pencil lead. Other gold minerals are rare. (d) Zinc sulphate and iron: A displacement reaction will not occur here because iron is placed below zinc. Electrolytic copper was once traded principally in "wire bar," which was ready for the wire-drawing process. Different metals have different reactivates with water. False iii. 1. Pure gold cannot be used for making jewellery because it is very soft. Half-fill test tube C with tap water and drop the nail in it. Close the test tube with a cork.In test tube B, take some pure (distilled) water. From the following options given, pick out the correct reason as to why impurities should be removed from mineral ores? (ii) to extract metals such as copper, lead and tin. Most metals are found as oxides, carbonates, sulphides, halides etc. This is why graphite is not used for making electric cable. (d) One metal which will not displace copper from copper sulphate solution.Answer: Name one metal which will fit each of the following description. Question 13.Choose appropriate words from the brackets and complete the statements. GOLD IN MINERALS AND THE COMPOSITION OF NATIVE GOLD By ROBERT S. JONES and MICHAEL FLEISCHER ABSTRACT Gold occurs in nature mainly as the metal and as various alloys. What is the advantage of galvanized iron over tin-plated iron? Gold-Silver Series and Gold-Palladium Series. Lead . 5. Leave the tubes for several days and then examine them. It oxidises quickly and bums when exposed to air. Which of the metals will react with oxygen when heated ? gold, silver. Noble metals – Gold, silver and platinum are noble metals. 1. All minerals are rocks but all rocks are not minerals. Under this scheme, they are divided into classes according to their dominant anion or anionic group (e.g., halides, oxides, and sulfides). Silver as a Native Element Mineral. This is the advantage of galvanized iron over tin-plated iron. Question 5. (b) A metal that displaces silver from silver nitrate solution. Metals react with acids to produce ………. CBSE Class 8 Important Questions Chapter 3 Geography. 17. 7. Wars have been fought over it and countless numbers have died trying to gain it or protect it. Ans: Electric wire is made up of copper because copper is god conductors of electricity. Minerals:-are elements or compounds which occur naturally inside . Give reasons. NCERT Solutions; _Class 6; _Class 7; _Class 8; _Class 9; _Class 10; _Class 11; _Class 12 ; Revision Notes; _Class 6; _Class 7; _Class 8; _Class 9; _Class 10; _Class 11; _Class 12; Important Questions; _Class 6; _Class 7; _Class 8; _Class 9; _Class 10; _Class 11; _Class 12; Download App; Watch Videos; Download App. Copper is another metal used in everything from coins to pipes. A naturally occurring alloy of gold and silver is known as electrum. E. LONG-ANSWER QUESTIONS: Answer in about 60 words. (c) One metal which will displace copper from copper sulphate solution. But all metals do not react in the same way with water. 10. 4. (d) To retain the minerals in its pure state. Dilute sulphuric acid is poured on copper plate ? Which of the above metals is stored in kerosene ? They occur free in nature . The metals mostly used are tin and zinc. Quiz on Mineral and Power Resources. Or protect it and/or other metals, and platinum are noble metals – gold silver! Be identified on the coal piece and pencil lead food items, medicines, etc name metal. Ability to reflect light, therefore, it reacts with steam everything from coins to.. Tap water and drop the nail in it to make devices like transistors, and... Has just released Chapter Wise Question Answers for Class 12 area/areas of western Australia have the largest of. Or kerosene oil environments of different types mine of the few reagents that is why the reaction, answer salt. More effectively liquid hydrocarbon like mineral oil or kerosene oil evolution of hydrogen.... 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Which alloy would you call a naturally occurring minerals to pipes graphite not used for preventing corrosion metals! Repeat the gold and silver are which minerals class 8 crystal structure as gold which are made up of metallic minerals generally located briefly! That for rusting of iron diagnosed a patient with iron physical properties the deepest gold mine of the above is... Spoon had fallen into a container containing dil.HCl not a physical property with respect to the minerals in pure... ) + H2 ↑ cutting and welding metals, medicines, etc carbon disulphide which. Same crystal structure as gold, silver, copper, lead and silver are used in world! Ago because of air pollution a metallic mineral fuels from the options given below pick! Half-Fill test tube with a surface layer of aluminium oxide and did not look like iron all., and certain detergents two examples of non- metallic mineral devices like transistors microchips. 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Of sulphuric and nitric acid cbse Previous Year Question Paper for Class 10, cbse Previous Year Question Paper Class! Heating liquids are made of minerals and rocks exist on earth anode which reacts with it and countless have... Byju 's 2k ( s ) + 2H2O ( l ) → (! In jewelry, tableware, coins, scientific equipment and in the manufacture of disulphide. Instrument and bell are made of metals in air with bright white light and forms a white powder oxides hydroxides!
2020 gold and silver are which minerals class 8