History of PT, Characteristics of Metals, Nonmetals and Metalloids. Bcaan TEACHER. Greatest variation in properties of the three groups (metals, nonmetals or metalloids) Nonmetals (have solids, liquids and gases) High luster, reflect light, malleable (metals.
![]()
Frank Cce Everyday Science Solutions for Class 8 Science Chapter 1 Crop Production are provided here with simple step-by-step explanations. These solutions for Crop Production are extremely popular among Class 8 students for Science Crop Production Solutions come handy for quickly completing your homework and preparing for exams. All questions and answers from the Frank Cce Everyday Science Book of Class 8 Science Chapter 1 are provided here for you for free. You will also love the ad-free experience on Meritnation’s Frank Cce Everyday Science Solutions. All Frank Cce Everyday Science Solutions for class Class 8 Science are prepared by experts and are 100% accurate.
Page No 63:Page No 64:Answer:
(c) 118
There are 118 elements known to us. Page No 64:Answer:
(c) both
Metalloids have the properties of both metals and non-metals. Page No 64:Answer:
(a) graphite
Graphite is used for making pencil lead. Page No 64:Answer:
(a) mercury
Mercury is a metal found in liquid state. Page No 64:Page No 64:Answer:
(a) sodium
Sodium reacts with hydrochloric acid and gives sodium chloride and hydrogen. Page No 64:Answer:
(c) aluminium
Aluminium is used in food packaging. Page No 64:Answer:
(a) arsenic
Arsenic is a metalloid. Copper, aluminium and iron are metals. Page No 64:Answer:
(c) graphite
Graphite is an allotrope of carbon that is used in making pencil lead. Page No 64:Answer:
1. Metals react with oxygen to form metal oxides.
2. Iron is more reactive than copper. 3. Metals usually displace hydrogen from acids. 4. A material that can be flattened into sheets by beating or rolling is called a metal. 5. Silver, gold and platinum are non-reactive metals. Page No 64:Answer:
Page No 64:Answer:
1. True 2. False Metals are generally hard with the exception of sodium and potassium, which can be cut with a knife. 3. False Aluminium is a metal. 4. True 5. True Page No 65:Answer:
Our country does not have enough industries to consume all the mined haematite. So, it is exported from India to countries like Japan and they sell it back to us at ten times the original cost. In order to increase the consumption of these mined haematite, government needs to increase the number of industries. To improve the quality of production, these industries should strive upon the necessary improvement in infrastructure. Page No 65:Answer:
Mercury is used in clinical thermometers because it is a good conductor of heat and is found in liquid state. Being a liquid, it expands when heated. Mercury also has a high boiling point. Hence, a slight change in temperature can be measured easily by the rise of the mercury column in the thermometer. It can also be used to measure high temperatures.
Page No 65:Answer:
Metals that are more reactive than hydrogen, replace hydrogen from its acids by a displacement reaction.
Word equation: Sodium + Hydrochloric acid → Sodium chloride + Hydrogen Non-metals do not react with dilute acids; therefore they cannot replace hydrogen from acids. Page No 65:Answer:
Non-metals are not sonorous. So, they do not produce sounds or metallic clinks. Hence, bells are not made of non-metals.
Page No 65:Answer:
Plastic or wooden handles are non-conductors of electricity. So, in order to protect the electrician from getting an electric shock or any kind of electrical accidents, the screw drivers used by an electrician have plastic or wooden handles.
Page No 65:Answer:
Aluminium is a metal used for packing food.
Page No 65:Answer:
Metals and non-metals are two main groups of elements.
Page No 65:Answer:
Sodium is a metal that can be cut with a knife.
Page No 65:Answer:
Helium and nitrogen are two gaseous non-metals.
Page No 65:Answer:
Mercury and gallium are found in liquid state.
Note: Gallium is liquid at room temperature but it becomes a solid below room temperature. Page No 65:Answer:
Gold, silver, copper and iron are highly ductile metals.
Page No 65:Answer:
Mercury is a metal which is a liquid at room temperature.
Page No 65:Answer:
Metalloids are elements that possess the characteristics of both metals and non-metals. Examples: silicon, boron, germanium, arsenic
Page No 65:Answer:
Chromium and nickel are two metals used for electroplating.
Page No 65:Answer:
Chlorine is used for purification of water.
Page No 65:Answer:
When metals react with oxygen, they produce metal oxides.
For example, when magnesium reacts with oxygen, it gives magnesium oxide. Word equation: Magnesium + Oxygen → Magnesium Oxide Dissolving magnesium oxide in water gives magnesium hydroxide. Word equation: Magnesium oxide + Water → Magnesium Hydroxide Now, when this solution is tested with red litmus, the red litmus turns blue. This shows that the solution is basic. Page No 65:Answer:
Following are the conditions necessary for the rusting of iron:
(i) Presence of air (oxygen) (ii) Presence of moisture (water) Page No 65:Answer:
Ductility is a property of metals. It means that metals can be drawn into thin wires. Example: Gold, silver, copper and iron are highly ductile metals.
Page No 65:Answer:
Word equation for the reaction of aluminium with hydrochloric acid:
Aluminium + Hydrochloric acid → Aluminium chloride + Hydrogen gas Word equation for the reaction of sulphur dioxide gas with water: Sulphur dioxide + Water → Sulphurous acid Page No 65:Answer:
When sodium oxide reacts with water, sodium hydroxide is produced. Word equation for the reaction of sodium oxide with water: Sodium oxide + Water → Sodium hydroxide Page No 66:Answer:
When a piece of iron is placed in copper sulphate solution, we would have the following observation:
Observation: The blue colour of copper sulphate will get reduced with time and the solution will turn green. Reddish brown precipitate of copper will deposit at the base of the container in which reaction is taking place. Conclusion: Iron is more reactive than copper because of which the displacement reaction occurs; copper is slowly displaced by iron. Word equation: Copper sulphate + Iron → Copper + Iron sulphate Page No 66:Answer:
Page No 66:Answer:
Elements are the purest substances that consist of only one type of atoms. They cannot be broken down further into simpler units.
Classification of elements: Elements are classified into metals, metalloids and non-metals. (i) Metals: The elements that are lustrous, hard, ductile, malleable, sonorous and good conductors of heat and electricity. (ii) Non-metals: The elements that are non-lustrous, brittle, non-ductile, non-malleable and poor conductors of heat and electricity. (iii) Metalloids: The elements that possess the characteristics of both metals and non-metals. Page No 66:Answer:
The shining on the surface of a metal is called its metallic lustre. Surfaces of metals are generally shiny when they are in their pure state. Due to this shining property of metals, they are used in making ornaments.
Example: (i) Copper is reddish brown and gold is generally yellow. (ii) Magnesium, silver and aluminium appear white. Page No 66:Answer:
Generally, metals react with acids and displace hydrogen from them. After the reaction, metal salts and hydrogen gas are obtained.
Word equation: Sodium + Hydrochloric acid → Sodium chloride + Hydrogen Noble metals like silver, gold, copper and platinum do not react with acids. Hence, no displacement of hydrogen takes place. Page No 66:Answer:
Copper forms a green layer on its surface on corroding. When copper is exposed to damp air for a long time, a coating of basic copper carbonate is formed. This coating is green in colour.
Word equation: Copper + Water + Carbon dioxide + Oxygen → Copper carbonate + Copper hydroxide No, aluminium does not rust in the presence of damp air because it does not react with water under ordinary conditions. Page No 66:Answer:
(a) Zinc: It is used to protect iron by the process of galvanisation.
(b) Iron: It is used as a catalyst in Haber's process during the production of ammonia. (c) Aluminium: It is used in making foils for packaging different materials like cigarettes, medicines and food. (d) Gold: Gold amalgam is used by dentists to fill tooth cavities. (e) Mercury: It is used in thermometers. Page No 66:Answer:
Silver gets deposited on the surface of copper when copper reacts with silver nitrate. The colourless solution turns blue. Copper displaces silver from silver nitrate and forms copper nitrate and silver. This reaction is called a displacement reaction.
Word equation: Silver nitrate + Copper → Copper nitrate + Silver Page No 66:Answer:
The following are two uses of phosphorous:
(i) It is used to manufacture phosphoric acid and superphosphate fertiliser. (ii) It is used to manufacture matchsticks, rat poison, alloys, fireworks and smoke screens. Page No 66:Answer:
Aluminium is used for making electrical transmission wires because it is a good conductor of electricity and its alloys can tolerate high voltage.
Page No 66:Answer:
Metal chlorides are formed when an acid reacts with a metal. Metal replaces the hydrogen from the acid and forms metal chloride. Hydrogen gas is also evolved.
Word equation: Sodium + Hydrochloric acid → Sodium chloride + Hydrogen gas Page No 66:Answer:
Noble metals are metals that generally show less reactivity or no reactivity with any reagent. They are lustrous. Hence, they are used in making ornaments.
Page No 66:Answer:
Following are two uses of sulphur:
(i) Primarily, it is used for making sulphuric acid. (ii) Sulphuric acid is used for making plastics, synthetic fibres, drugs, dyes, explosives, detergents, fertilisers and germicides. It is also used in beauty parlours and for vulcanisation. Page No 66:Answer:
Page No 66:Answer:
Metals are good conductors of heat. This can be explained with the help of the following experiment: Experiment: (i) Take different pieces of metals like iron, zinc or aluminium. (ii) Hold the pieces of metals using a clamp stand. (iii) Heat a piece of one metal using a burner. (iv) Check the temperature of the metal with a thermometer. (v) Repeat this experiment with each material. Observation: The temperature of each material will increase. Conclusion: Metals are good conductors of heat.
View NCERT Solutions for all chapters of Class 8
Metals are naturally-occurring substances that conduct electricity, have a metallic luster, are malleable and form cations. They can adversely affect human health in elevated doses – causing organ, neurological and reproductive damage and an increased risk of cancer. The toxicity relating to metals depends on their form in the environment.For environmental analysis, the term metals is expanded to include semi-metals and metalloids. They can be found in high concentrations in the environment because of:. Industrial activity. Mining. Chemical waste disposal.
Leaded gasoline. Paint. Leaching from acid rain.
Atmospheric depositionThe most commonly analyzed metals are arsenic, copper, chromium, nickel, silver, selenium and mercury. SGS metals and inorganics testing servicesWe provide a full-range of testing services for metals and inorganic compounds.
The process usually requires a digestion procedure to convert the metals into a soluble form. This is done using a variety of acid mixtures and other chemicals.Analysis is then performed using one of the following techniques:.
Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Atomic Absorption (Flame or Graphite Furnace). Cold-Vapor Atomic Absorption (CVAA). Ion Chromatography (IC). Cold Vapor Atomic Fluorescence (CVAFS)Mercury is often done via a separate analysis using either CVAA or CVAFS. Why choose SGS?We have a global network of technical experts ready to help you select the correct methods for your metals and inorganics testing requirements.
Selection will consider regulatory requirements, the required analytes and detection limits. Working with SGS will ensure testing and analysis is efficient and meets your data objectives.For more information on metals and inorganics testing, contain your local SGS office.
![]() Comments are closed.
|
AuthorWrite something about yourself. No need to be fancy, just an overview. Archives
March 2023
Categories |