ICSE Chemistry Prodigy Class-8 Question Bank

(1) The change of state from solid to liquid is called ________.

(2) Solid is very difficult to ________.

(3) ________ have no definite shape.

(4) The change of liquid to gas is called ________.

(5) The process in which solid directly changes into gas is called ______.

(1) LPG means liquefied petroleum gas

(2) Solid changes into liquid; this is called fusion

(3) In gaseous state, the interparticles space are very less

(4) The zig-zag motion of gas particles is called spreading motion.

(5) Matter can change from one form to another on changing temperature and pressure.

(1) A gas exerts pressure on the walls of the container. Why?

(2) What is melting point?

(3) Out of solid, liquid and gas, which state of matter has the least kinetic energy?

(4) What is solidification?

(5) What is Brownian motion?

(1) Write the three characteristics of solid.

(2) Explain Brownian motion

(3) Write the kinetic theory of matter

(4) A substance has no mass. Can we regard it as matter?

(5) Give the reason: Naphthalene balls disappear with time without leaving any solid.

(1) Write the three differences between solid, liquid and gaseous state.

(2) Explain the kinetic theory of matter.

(3) What do you mean by the change of state? Write the flow chart showing the complete cycle of change of state

(4) Describe an experiment to demonstrate that a substance absorbs heat during melting without change in its temperature.

(1) Changes in which the formation of new substances takes place are called ________.

(2) Melting of ice is a ________ change.

(3) Burning of wood is a ________ change

(4) Revolution of the Earth around the Sun is a ________ change

(5) A small plant changes into a tree is a ________.

(1) Cooking of rice is a physical change

(2) Breaking of a china dish is a chemical change

(3) Cutting of wood into pieces is a chemical change.

(4) Rusting of iron is an irreversible change

(5) Eruption of a volcano is a reversible change.

(1) What are slow changes?

(2) Write the three examples of physical change

(3) What kind of change is shown by tearing of paper?

(4) Give one example of physical change which occurs by the action of heat.

(5) What is a chemical change?

(1) State one instance where water undergoes a physical change and one in which it undergoes a chemical change

(2) How would you show that the setting of curd is a chemical change?

(3) Explain why burning wood and cutting something into small pieces are considered two different types of changes.

(4) Write the three characteristics of physical changes.

(5) Write the three characteristics of chemical changes.

(1) When a candle burns, both physical and chemical changes take place. Identify these changes. Give another example of a familiar process in which both chemical and physical change take place.

(2) Give four differences between physical and chemical changes.

(3) What happen when magnesium oxide is dissolved in water? Write a word equation for this process. Name the type of change which takes place

(1) Symbol of gold ________.

(2) Compounds have ________ melting points .

(3) Sugarcane juice is a mixture of ________, water and many other substances.

(4) Separation of components is done to obtain a ________ substance.

(5) Boiling point of pure water is ________ than that of impure water.

(1) A pure substance has a fixed melting and boiling point.

(2) compounds are pure substances .

(3) Separation of components of a mixture is a useful process.

(4) Nitrogen molecule is formed by mutual sharing of electrons.

(5) Tap water and pond water are alike

(1) What substance is used for loading the clay particles suspended in muddy water?

(2) By which method is sugar separated from wheat flour?

(3) Name the method used in separate cashewnut of different size.

(4) Write the opposite process of condensation

(5) Name the process used to recover salt from sea water.

(1) What is the use of alum in loading?

(2) What is the use of decantation?

(3) How will you separate a mixture of sand and salt?

(4) Write short notes on : (i) Distillation (ii) Sieving (iii) Sublimation

(5) Explain diffusion.

(1) Explain the fractional distillation with an example

(2) Explain the filtration with an example

(3) Suggest a suitable technique to separate constituents of the following mixtures. Also, give reason for selecting the particular method. (a) Iron from sulphur (b) Chalk powder from water

(1) An ion which has a negative charge is called a ..................

(2) The mass of hydrogen atom ................. g.

(3) Isotopes of an element differ in the number of .................. in their nucleus.

(4) The outermost shell of an atom is known as .................

(5) Neutrons are ............... particles having mass equal to that of protons.

(1) Thomson proposed that the nucleus of an atom consists proton and neutrons

(2) An electron has a mass that is much less than a proton.

(3) An atom on the whole as neutral.

(4) The maximum number of electrons in the first shell can be 8.

(5) α-particles are the same as helium atom

(1) What are cathode rays?

(2) How many times is a neutron heavier than an electron?

(3) What are Rutherford’s experiment and atomic model called?

(4) In an atom, which shell has the least energy?

(5) What are anode rays?

(1) How will you represent the fundamental particles, electrons, protons and neutrons?

(2) Why was Thomson’s atomic model compared with a watermelon?

(3) Write the comparative mass of electron, proton and neutron.

(4) How was neutron discovered by James Chadwick?

(5) Write the definition of atomic number and mass number

(1) Explain the Bohr’s atomic model

(2) Explain Rutherford’s model of is atoms and write observation and conclusion of a-ray scattering experiment.

(3) Compare and contrast Rutherford's and Bohr's model of atom.

(1) A chemical equation provides information on the ________ of the substance and the reaction condition

(2) The symbol “aq” in a chemical equation represents the physical state of the substance as ________.

(3) Reaction in which heat is absorbed is represented by ________ sign.

(4) Unbalanced equation is known as ________.

(5) In a chemical reaction, the sum of the masses of the reactants and products remains unchanged. This is called ________.

(1) In a chemical equation, the products are written on the right-hand side.

(2) A chemical equation can be balanced easily by altering the formula of a reactant or product.

(3) A balanced chemical equation obeys the law of conservation of mass.

(4) Na+ is a anion.

(5) Down arrow (¯) indicates gas evolved.

(1) What is symbol of an element?

(2) What is a chemical equation?

(3) Give an example of exothermic reaction.

(4) What is molecular formula of a compound?

(5) What is atomic mass?

(1) Write the characteristics of a chemical equation

(2) Write the definitions of the following : (i) Reactant (ii) Balanced chemical equation

(3) Balance the following chemical equations : (i) H₂ + N₂ - NH₃ (ii) MnO₂ + HCl - MnCl₂ + Cl₂ + H₂ O

(4) Write the notation used for representing: (i) a precipitate (ii) a gas (iii) a liquid

(5) Write a short note on radicals.

(1) Explain the modern concept of valency?

(2) Copper having electronic configuration 2, 8, 18, 1 that exhibits variable valency. Give a reason for the same & name the compounded CuCl & CuCl2 .

(3) State information provided by a chemical equation. Chemical equations suffer from a number of limitations. State main limitations of a chemical equation.

(1) Magnesium ribbon burns in the air on heating with the formation of a white powder called ________.

(2) The substances which undergo chemical change are called ________.

(3) AgNO3 + NaCl → AgCl + ________

(4) Decomposition of potassium chlorate on heating in the presence of manganese dioxide is called________.

(5) Unbalanced reaction is also known as ________.

(1) The number of atoms of each element is conserved in any chemical reaction.

(2) Hydrogen sulphide has a rotten egg smell.

(3) Rusting of iron is a fast reaction

(4) The reaction between hydrogen and chlorine is an example of combination reaction.

(5) A black residue is formed when sugar is heated

(1) What is neutralisation?

(2) What is metal reactivity series?

(3) What are oxides?

(4) What do you mean by catalyst?

(5) Give two examples of enzyme.

(1) What do you mean by precipitation? Give one example

(2) Write the definitions of the following with one example each : (i) Addition reaction (ii) Decomposition reaction (iii) Displacement reaction (iv) Double displacement reaction

(3) Write the importance of metal reactivity series

(4) Write the definitions of the following with one example each : (i) Acidic oxide (ii) Basic oxide (iii) Amphoteric oxide (iv) Neutral oxide

(5) Define exothermic reaction with an example.

(1) What do you observe when : (i) Phenolphthalein is added to NaOH solution? (ii) Red litmus paper is dipped in NaOH?

(2) Complete and balance the following : (i) CaCO CO ----------->Heat _______ + CO2. (ii) Zn + H2 SO4 ------------> ZnSO4 + .............

(3) Give reasons for the following: (i) Burning a paper is a chemical change (ii) Freezing of water to ice and evaporation of water are physical changes.

(1) Large part of the Earth’s surface is covered by ________.

(2) Water has maximum density at ________ temperature.

(3) Water has maximum density at ________ temperature.

(4) Boiling removes the ________ hardness of water.

(5) Water can exist in ________ states.

(1) Oceans are the major sources of drinking water.

(2) Our body contains 90% water

(3) The groundwater is actually the rainwater.

(4) Anhydrous substances use a drying agents

(5) Permanent hardness of water can be removed by boiling of water.

(1) What is the freezing point of water?

(2) How much amount of water is found in human blood

(3) Name the four main sources of water.

(4) What is surface water?

(5) Explain the state of water.

(6) Why is water a universal solvent?

(1) Write the five benefits of water

(2) Why is water very precious for all living beings?

(3) Explain H2 O as a compound.

(4) Explain the anomalous expansion of water for aquatic plants and animals.

(5) Why does ice float on water?

(1) What happens when : (i) Coke reacts with water at 100°C. (ii) Calcium oxide reacts with water. (iii) Nitrogen pentaoxide reacts with water.

(2) Write the differences between suspension and colloidal solution.

(3) Explain the following terms : (i) Brownian movement (ii) Tyndall effect (iii) Crystallisation

(4) Explain water pollution and write the causes of water pollution.

(5) Explain the water cycle.

(1) Hydrogen is the first and ________ element

(2) Hydrogen constitutes about ________ per cent by weight of the Earth’s crust

(3) Iron reacts with hydrochloric acid to produce ________ with hydrogen gas.

(4) Water gas is a mixture of hydrogen and ________.

(5) Reduction is the addition of hydrogen or ________ element.

(1) Hydrogen is a diatomic molecule

(2) Concentrated nitric acid can be used for the preparation of dihydrogen

(3) Rancid foodstuff changes the smell and taste.

(4) Hydrogen is a oxidising agent.

(1) Write the names of three isotopes of hydrogen.

(2) What is oxidation?

(3) Write the two examples of non-electrolytes.

(4) What is hard water?

(5) Which gas is produced when sodium reacts with sulphuric acid?

(1) What happen when zinc reacts with sodium hydroxide?

(2) Give reasons for the following. (i) Hydrogen can be used as a fuel. (ii) Nitric acid is not used for the preparation of dihydrogen.

(3) Write any three physical properties of dihydrogen.

(4) Give answers of the following : (i) Name two metals which give hydrogen with cold water. (ii) The process in which oxygen is added or hydrogen removed

(1) Describe the preparation of dihydrogen in the laboratory

(2) Explain the commercial preparation of dihydrogen by Bosch process.

(3) Explain the electrolysis of water

(4) . Complete and balance the following equations : (i) H2 + Cl2 -----------> ............... (ii) H2 + S ------------>............... (iii) 2 1100 C CH4 C ---------------> ............... (iv) Fe3 O4 + 4H2 -------------> ............... + 4H2 O

(5) Write any four uses of hydrogen.

(1) Diamond and graphite are ________ forms of carbon

(2) Lamp black, charcoal and coal are examples of ________ allotropic forms of carbon.

(3) Lack of oxygen and excess of carbon dioxide in the blood causes ________.

(4) In Buckminsterfullerene, carbon atoms are held together by ________ bonds.

(5) All carbonates upon reaction with dilute acids give ________.

(1) Graphite is a crystalline form of carbon

(2) Carbon is the fifth most abundant element in the universe.

(3) The allotropes of the same element have different physical properties but may have the same chemical properties.

(4) Water gas is a mixture of carbon monoxide and hydrogen.

(5) Activated Charcoal is a good conductor of heat and electricity

(1) What is catenation?

(2) Name one crystalline allotrope of carbon

(3) What is destructive distillation?

(4) Write the uses of lamp black

(5) What is carbonisation?

(6) Write the industrial uses of CO2 .

(7) Why is carbon monoxide considered as a poisonous gas?

(1) What is meant by the term 'fullerenes'?

(2) Give four physical properties of graphite

(3) How is wood charcoal made?

(4) State the poisonous nature of carbon monoxide.

(1) Write equations to show the reaction of carbon dioxide with: (a) H2 O (b) Ca(OH)2 (c) Mg (d) K2 O (e) NaOH

(2) Write any two methods used for preparing CO2 . Write two uses as well

(3) Write the uses of the following: (a) Diamond (b) Lamp black (c) Charcoal (d) Graphite (e) Soot

(4) Describe the formation of coal. Explain the four types of coal in brief.