(a) Most liquids that conduct electricity are solutions of , ______________ and … What is CFL ? For example: All metals including metal wires, copper wires, aluminium foil, etc. (d) Zinc chloride from zinc. (b) What happens during a chemical reaction ? Fill in the blanks in the following statements: (a) When carbon dioxide is passed through lime … Each man carries within himself his own mountain peak. CuSO 4.5H 2 O (s) ⇋ CuSO 4(s) + 5H 2 O (g) (d) Displacement. Answer: Combustion and Flame Class 8 Notes, Question Answers. Also, go through the concept of interconversion of matter with our concise ICSE Class 8 Chemistry notes by experts. (d) chemical energy into magnetic energy (c) Sodium chloride If not, what can we do to make it conducting ? Which of the following is a chemical property of water? Method : Question 2. Question 3. Selina Class 8 Chemistry ICSE Solutions Physics Biology Maths Geography History & Civics. 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An example of a chemical property is reactivity. What is electrolysis ? e.g. (b) Oxalic acid No, it is not advisable for electrician to carry out electrical repairs during heavy downpour because water is a good conductor of electricity and the person can get shock. Concise Chemistry - Middle School for Class 8 ICSE Author: Namrata Publisher: Selina Publishers Language: . The rainwater showed deflection with the tester because it is not as pure as distilled water. (d) Nitric acid (c) Name three biochemical catalysts found in the human body. Question 1 . Yes, the solution does conduct electricity. Answer: As water is a good conductor of electricity so it can cause electrocution. (c) Blue litmus turns red in an acid solution. Define good conductors and poor conductors or insulators. (a) A reaction in which two or more substances combine to form a single substance is called a combination reaction. Question 2. A child staying in a coastal region test the drinking water and also the seawater with his tester. What precautions should be observed when doing electroplating ? It causes rise in temperature. Name the gases formed when electric current is passed in water containing a few drops of acid ? Question 8 Write down any 4 characteristics of chemical change. What is the basic principle of electric pen ? The remaining previously published questions and answers on the use of the general chapter 2.9.40 (former questions and answers 2, 3, 5 and 6) are still valid and remain published as questions and answers 2 to 5. (i) Zinc, displaces copper from copper sulphate solution. As pure water is free of salts and thus it is an insulator so to make pure water conducting, we can add some salts or acid to it. The temperature around the electroplating equipment should be optimum. On the other hand the loss of copper from the solution is regained from the impure copper rod which is attached to the positive terminal of the battery. Conditions necessary for a chemical change or reaction are Question 6. (b), Question 3. SURVEY . Why? Or, the bulb is fused? Example. Get sample questions & answers on Physical and Chemical Changes for Grade 7. Question 8 . How can the magnetic effect be used as a tester ? When the free ends of a tester are dipped into a solution, the magnetic needle shows deflection. Your tester with two free ends of the wire is ready. Zn + CuSO4 (aq) → ZnSO4 (aq) + Cu (ii) Iron piece when added to copper sulphate solution, copper is displaced. Answer: Is it safe for the electrician to carry out electrical repairs outdoors during heavy downpour? (a), Question 4. Change in color b. Magnesium ribbon burns with a dazzling flame in air (or oxygen) and changes to a white substance magnesium oxide. Question 17. Activity 4 (NCERT Textbook, Page 175) Why electric fires are extinguished with either using CO 2 extinguisher or mud but not water? A chemical reaction in which the direction of a chemical change can be reversed by changing the conditions under which the reaction is taking place is called a reversible reaction. It gets deposited on the Question 9. (i) The wires in the circuit may be loosely connected. A tester is used to check the conduction of electricity through two liquids, labelled A and B. Chemical Effects of Electric Current Class 8 Extra Questions Short Answer Questions. Classify the following as a physical or chemical change: Tearing a piece of paper into 100 pieces. (b) What are (i) positive catalysts and (ii) negative catalysts? Question 9 Why is it always advised not to play with fireworks? (b) Silver chloride from silver nitrate. Give two examples of chemical changes in daily life. He finds that the compass needle deflects more in the case of seawater. You would conclude that. Give one example each of which illustrates the following characteristics of a chemical reaction: (a) evolution of a gas (b) change of colour (c) change in state Answer: (a) When Zinc reacts with dil. Take the tray from inside a discarded matchbox. Is air an insulator or conductor of electricity ? C + O2 → CO2 + heat. Chemical Engineering MCQ questions and answers for an engineering student to practice, GATE exam, interview, competitive examination and entrance exam. A property which makes the object smell or taste different. Practice MCQ Questions for Icse Class 8 Chemistry Chapter 2 Physical And Chemical Changes with Answers to improve your score in your Exams. If the magnetic compass shows deflection glows, it is a conductor, but if it does not deflect, it is an insulator. Question 2. N2 + O2 + heat → 2NO (g) (ii) Decomposition of calcium carbonate into carbon dioxide and calcium oxide when heated to a 1000°C. Combustion is defined as a chemical change in which both heat and light are produced at the same time in the presence of oxygen and the composition of substance is also changed. Answer: (a) Carbon dioxide present in the atmosphere is trapped by infrared radiations, gives rise to temperature which is exothermic reaction. Answer: (d) semi-insulator (e) Soluble bases are called alkalis. of distilled water in a clean and dry beaker. Solution: Download free printable worksheets for CBSE Class 8 Science with important topic wise questions, students must practice the NCERT Class 8 Science worksheets, question banks, workbooks and exercises with solutions which will help them in revision of important concepts Class 8 Science. Which properties of chromium make it useful for electroplating on iron ? The bulb does not glow in the setup shown in Fig. Take 250 ml. The seawater contains a huge amount of salts in comparison to drinking water, hence the seawater is a better conductor of electricity and it produces a stronger magnetic field in the wire and hence deflects the compass needle more. Question 12. What colour is the coating? Question 9 Why is it always advised not to play with fireworks? If the current in the circuit is small, how can we test its presence ? Question 11 Define (1) galvanization How can you make a tester for testing whether a given material is a conductor or an insulator ? Can we do electroplating on it to protect is from corrosion ? It causes fall in temperature. Answer: About this quiz: All the questions on this quiz are based on information that can be found at Chemistry: Chemical Bonding . Pour a cupful of water in a glass/ plastic bowl. Ex. Water is a solution of salts and so it is a good conductor of electricity. Answer: Change in temperature. Firemen shuts off the main electrical supply for the area because water is a good conductor of electricity and the firemen can get electrocuted. Collect a few small plastic or rubber caps of discarded bottles and clean them. Answer: So she collected some rainwater in a clean glass tumbler aifd tested it using a tester. We should not do the experiments on electricity by using electric supply from the mains because there is large amount of current and the person using it can get electrocuted. Chemical Effects of Electric Current Class 8 Notes, Question Answers, Explanation February 9, 2019 by SuccessCDs Team in CBSE Class 8 Science Lessons Explanation, Notes, NCERT Question Answers Chemical Effects of Electric Currents Class 8 Science Chapter 14 as per NCERT Book used in CBSE and other Schools. Can you ex¬plain the reason? Shape change. (b) cathode (Instead of carbon rods, you may take two iron nails about 6 cm long.) How can he do it ? Dinesh can study the chemical effect of current at home very easily. Question 1. (a) acids, bases, salts Bonds… Use our ICSE Chemistry Class 8 revision notes to understand the physical and chemical changes of matter. (b) The passage of an electric current through a solution causes _______ effects. Question 8. Compass needle shows deflection due to magnetic effect of electric current. (f) When few drops of dilute sulphuric acid is added to barium chloride solution, a white precipitate of barium sulphate is formed. Wood is cut c. Bread is baked d. Wire is bent 9. Question 11. Question 7. Question 14. When lead nitrate is heated, it breaks into lead monoxide, nitrogen dioxide and oxygen. Can you explain the reason? The bulb in the tester does not glow when current is passed through it. (b) When blue coloured copper sulphate reacts with hydrogen sulphide gas, a black coloured substance copper sulphide is formed. Question 1. [NCERT] Answer: Free PDF Download - Best collection of CBSE topper Notes, Important Questions, Sample papers and NCERT Solutions for CBSE Class 8 Science Chemical Effects of Electrical Current. (e) Ammonia from nitrogen. Answer: Question 11. Conductors : lemon juice, tap water. Why the iron cans are electroplated with tin ? (b) ammonium chloride is dissolved in water. Activity 7 (NCERT Textbook, Page 177) Use the tester to test whether distilled water conducts electricity or not. (b) If the soil is acidic it can be treated with base like quick lime, to make it neutral. Place a small compass needle inside it. An example of a chemical change or reaction is: A mixing salt in water B burning wood C defrosting frozen food: 7. Answer: (a) Any chemical change in matter which involves transformation into one or more substances with entirely different properties is called a chemical reaction. It is found that the bulb of the tester glows brightly for liquid A while it glows very dimly for liquid B. Name one non-metal which a good conductor of electricity. CaO + H2O → Ca (OH)2 + Heat. To her surprise she found that the compass needle showed deflection. This collection of 10 chemistry test questions tests your ability to balance a chemical reaction.These equations will be balanced for mass. Question 11 Define (1) galvanization (Remember to wash and wipe the ends of tester after testing each liquid). Question 1. Size Change. normally the adolescence starts from the age of 11 and lasts up to 18 or 19 years of age. Graphite. (g) In the type of reaction called double decomposition reaction, ions two compounds exchange their positive and negative radicals ions respectively. 14.5. may cause the magnetic needle to deflect. Multiple Choice Questions for Icse Class 8 Chemistry Chapter 2 Physical And Chemical Changes (c) Displacement reaction: A reaction in which a more active element displaces a less active element from a compound is called displacement reaction. Answer: Answer: So the practice set of Chemical Equilibrium with Important Questions And Answers helps students of class 11 and also for students studying for various competitive exams. Give three applications of chemical effect of current. Phosphoric acid acts as a negative catalyst to decrease the rate of the decomposition of hydrogen peroxide. Answer: (a) When Zinc reacts with dilute sulphuric acid, hydrogen gas is evolved with an effervesence. . (b) (i) Positive catalyst: When a catalyst increases the rate of chemical reaction, it is called positive catalyst. (c) negative Chemical Equilibrium is the most important and interesting chapter of Chemistry. Short answer type Question 7 Differentiate between physical and chemical change with 2 examples of each. upon publication. Gradually, a layer of copper builds up on the plate. Answer: Chemical Equilibrium is the most important and interesting chapter of Chemistry. A + B → AB e.g (i) When iron and sulphur are heated together, they combine to form iron sulphide. So she collected some rainwater in a clean glass tumbler and tested it using a tester. (f) Ammonia is brought in contact of hydrogen chloride.gas. (c) Nitrogen dioxide from lead nitrate. What results do you obtain? Register online for Science tuition on … Question 12. Question 6. Now test if the tester is working or not. Good/Poor Conducting Liquids. Selina Publishers Concise Chemistry for Class 8 ICSE Solutions all questions are solved and explained by expert teachers as per ICSE board guidelines. (c) If you pass current through copper sulphate solution, copper gets deposited on the plate connected to the ________ terminal of the battery. Question 4. Answer: Start studying Grade 8 Science: Physical and Chemical Changes. Answer: How do the following help in bringing about a chemical change? So, whenever you feel any problem, just refer to the solution book. Support your answer with one example for each of them. Answer: (a) Some chemical reactions take place when reactants are subjected to high pressure. FeSO4 (aq) + 2NaOH (aq) → Fe(OH)2 ↓ + Na2SO4(aq). Question 21. Distilled water is a Short Q&A: Q1: Explain physical reaction along ... Q22: A part from new products, many other things accompany a chemical change, what are those things? (i) When nitrogen and oxygen together are heated to a temperature of about 3000°C, nitric oxide gas is formed. (d) photodiode Question 8 Write down any 4 characteristics of chemical change. Pour one teaspoon of lemon juice or vinegar in one cap. The free copper gets drawn to the plate connected to the negative terminal of the battery and gets deposited on that plate. Short answer type Question 7 Differentiate between physical and chemical change with 2 examples of each. Why ? (i) When carbon bums in oxygen to form carbon dioxide, a lot of heat is produced. It cannot be said for sure that liquid does not conduct electricity because : Question 2. Answer: Define exothermic and endothermic reactions. (c) Blue litmus paper is dipped in dilute hydrochloric acid. Register online for Science tuition on Vedantu.com to score more marks in your examination. A child staying in a coastal region tests the drinking water and also the seawater with his tester. Explain why they do this. A. In a chemical reaction, the chemicals one starts with are called the: A reagents B reacting chemicals C products: 8. [NCERT] Revised topics are marked 'New' or 'Rev.' [NCERT] Answer: It cannot be said for sure that liquid does not conduct electricity because : may be the cells are weak. First and second cap with acid and base respectively, conducts electricity whereas third cap having sugar dissolved in distilled water do not conduct electricity. Add a little sugar to the distilled water in the third cap and dissolve it. Answer: Do you find a coating over it? (b), Question 5. A metal is released in the electrolysis of a salt. It also throws light over the chemical reactions, physical and chemical changes related to matter, Hydrogen and water. Deposits can be seen in containers uses for storing water. Question 2. Oxygen bubbles are formed on the electrode connected to the positive terminal of the battery and hydrogen bubbles are formed on the other electrode. Students are advised to practice and understand all the questions accordingly. Answer: The materials that conduct electricity through them are called good conductors whereas those that do not conduct electricity are called poor conductors or insulators. answer choices . This page is intended to provide advice to Marketing Authorisation Holders of centrally authorised medicinal products about classification of changes to the Marketing Authorisation post-authorisation and certain variation classification categories. Answer: Chapter 10 - Reaching the Age of Adolescence. Question 1. What are insulators ? List the possible reasons. (c) semi-conductor Hydroxyl ions (OH )move towards the anode and oxygen is collected on it. (a) Most liquids that conduct electricity are solutions of , … Answer: Again test. Jaya sets up a circuit as given below. Question 6. Question 4. During electrolysis of water, why does hydrogen collect on cathode and oxygen collect on anode ? CBSE Class 7 Science Physical and Chemical Changes Worksheets with Answers for Chapter 6 in PDF format to download prepared by expert Science teachers from latest edition of CBSE(NCERT) books. But the bulb does not glow. Combustion and Flame Class 8 Notes, Question Answers. Explain your answer. Which is an example of chemical change? Hydrogen and Oxygen. Chemical Effects of Electric Current Class 8 Extra Questions Higher Order Thinking Skills. Change in shape c. Change in energy d. Change in odor 10. The electrode, connected to the positive terminal of a battery, is called when potassium chlorate heated to 700°C decomposes to evolve oxygen gas, when MnO2 is added the decomposition takes place at 300°C (ii) Negative catalyst: When a catalyst decreases the rate of chemical reaction it is called negative catalyst. Record your observations in Table 14.1. Does the bulb of the tester glow? Solution: A chemical reaction is the process of breaking the chemical bonds of the reacting substances (reactants) and making new bonds to form new substances (products). Does distilled water conduct electricity? Chemical change is the change in which substance loses its properties and form new type of the substance which is different from the properties of the reactants.. Chemical change is brought about by addition, decomposition, exchange of atoms or molecules and the process by which chemical change occurs is called chemical reaction.. 20 Questions Show answers. What is a chemical change? (c) The reaction between hydrogen sulphide and chlorine (both gases) produces sulphur (solid) and hydrogen chloride (gas). The ease with which a metal in solution loses electron(s) and forms a positive ion decreases down the series, i.e. Repeat the activity with other liquids such as tap water, vegetable oil, milk, honey. Question 1. The filament of the bulb is heated due to current and then it glows. When electric current is passed through copper sulphate solution, the copper sulphate breaks up into copper and sulphate ions. Which one of the following is a weak electrolyte ? So, the fire¬men shut off the electric supply before spraying water to save themselves and other people from electrocution. (i) liquid A is a better conductor than liquid B. So, the compass needle showed deflection. Answer: Answer: Physical and Chemical Changes, CBSE Science Class 7 Chapter Wise Solved Q&A. Give two examples of each of the following oxides. Answer 11: (ii) Process – B is a chemical change. Question 1 . Take a filter paper soaked in potassium iodide solution to which a pinch of starch is added. Answer: (a) magnetic energy into chemical energy Format, Eligibility Criteria, Documents Required, BIS Certificate | How to Get BIS Certified? and ………….. Maharashtra Class 8 Science General Science -Solutions Solutions are created by experts of the subject, hence, sure to prepare students to score well. No, it is highly dangerous to carry out the electrical repairs outdoors during the heavy downpour. Chromium is used for electroplating because it has a shiny appearance, does not corrode and is scratch resistant. Answer: We cannot make the whole article from it because it is a very costly metal. What do you observe when (a) dilute sulphuric acid is added to granulated zinc? AB + C → CB + A e.g. Also, use our NCERT solutions for Class 8 Science Chapter 8 to understand the difference between a zygote and a foetus. Jake three clean plastic or rubber caps of bottles. (iii) The cells may be used up. Practice MCQ Questions for Icse Class 8 Chemistry Chapter 2 Physical And Chemical Changes with Answers to improve your score in your Exams. 1. Multiple Choice Questions for Icse Class 8 Chemistry Chapter 2 Physical And Chemical Changes This process is known as chemical effects of current. Chemical Engineering MCQ questions and answers especially for the Chemical Engineer and who preparing for GATE Exam. Question 13. (a) Most liquids that conduct electricity are solutions of ______ , ______ and ______ The decomposition of an electrolyte when electricity is passed through it, is called (b), Question 6. (c) Wasp sting is treated with vinegar. So the practice set of Chemical Equilibrium with Important Questions And Answers helps students of class 11 and also for students studying for various competitive exams. LED is Light Emitting Diode. 1. Photosynthesis. Question 3. Decoration of articles by giving them a layer for e.g., silver plating on cutlery. Chapter 10 aims to give you answers on what are the chemical and physical changes which take place in humans when they reach the age of adolescence and puberty. (b) Decomposition reaction: A reaction in which a compound breaks up due to the application of heat into two or more simple substances is called decomposition reaction. Changes of colour of solutions may occur depending on what solution and electrodes are used. What are electrodes ? Or, your cells are used up? (iv) None of these processes is a chemical change. Question 7. Which out of the following does not conduct electricity ? In what proportion the two products from electrolysis of water are obtained ? X Your answer: For webquest or practice, print a copy of this quiz at the Chemistry: Chemical Bonding webquest print page. Place them in fresh lemon fruit. (i) The chemical reaction between hydrogen and chlorine is a combinaton reaction (j) When a piece of copper is added to silver nitrate solution, it turns blue in colour. What is the disadvantage of electroplating done in the factories ? (You may obtain distilled water from your school science lab. Solution: Question 9. Answer: The characteristics of a chemical change are following: 1. What do you find? ... Classify the following as a physical or chemical change: A reaction takes place, and the product is different than what you started with. Fe + CuSO4 → FeSO4 + Cu. The compass needle should show deflection. Question 4. Monday 01st February 2021. a. Density b. sulphuric acid. (a) Aluminium The reaction can be represented as 2Mg + O2 → 2MgO (white powder) (f) Ammonia and hydrogen chloride, both compounds, combine to form a compound, ammonium chloride. What do you observe when (a) an acid is added to a basic solution. 14.4). (a) anode Question 5. Who Can Apply? O 2. answer choices . Question 11. 30 seconds . State of matter change. The process that you saw in Activity 14.7 is used for purification of copper.

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