Class 9 Science CBSE Important Question Chemistry Matter in our Surroundings, Is matter around us pure, Atoms and Molecules, Structure of Atom

  by RBeI


  1. Fill in the Blanks
  1. Evaporation of a liquid at room temperature leads to a ______ effect.
  2. The phenomenon of change of a liquid into the gaseous state at any temperature below its boiling point is called ______
  3. The laboratory thermometers and the clinical thermometer are calibrated in __________
  4. 0° C = _______ K
  5. The temperature is recorded by ______
  6. The thermometers with Fahrenheit scale are calibrated from _____
  7. The process of freezing is the reverse of __________
  8. The process of condensation is the reverse of _______
  9. The pressure is ______ at sea level.
  10. Evaporation of a liquid is always accompanied by ______ in temperature or cooling.
  1. Multiple Choice Question
  1. A few substances are arranged in the increasing order of forces of attraction between their particles. Which one of the following represents a correct arrangement?
  1. Water, air, wind
  2. Air, sugar, oil
  3. Oxygen, water, sugar
  4. Salt, juice, air
  1. On converting 25°C, 38°C and 66°C to Kelvin Scale, the correct sequence of temperature will be:
  1. 298K, 311K and 339K
  2. 298K, 300K and 338K
  3. 273K, 278K and 543K
  4. 298K, 310K and 338K
  1. The property to flow is unique in fluids. Which one of the following statement is correct?
  1. Only gases behave like fluids
  2. Gases and solids behave like fluid
  3. Gases and liquid behave like fluids
  4. Only liquids are fluids
  1. During summer, water kept in an earthen pot become cool because of the phenomenon of:
  1. Diffusion
  2. Transportation
  3. Osmosis
  4. Evaporation
  1. The rate of evaporation decreases with increase in:
  1. Surface area
  2. Temperature
  3. Humidity
  4. Wind speed
  1. The state of matter which have fixed volume but lack definite shape is:
  1. Solid
  2. Liquid
  3. Gas
  4. Plasma
  1. Write True or False
  1. The term vapour represent the gaseous state of a substance that exists as a liquid or solid
  2. -273 K = 0°C
  3. Solid cannot flow from one place to another
  4. An absolute temperature scale is the Celsius scale
  1. Short questions and answers
  1. Which substance in its gaseous state is called vapour?
  2. Name two gases supplied in homes and hospitals in compressed form.
  3. Expand: (a) CNG (b) LPG
  4. Name the term used to describe the mixing of copper sulphate and water kept in a beaker on its own.
  5. Name the particles which make up matter.
  1. Long Question and Answer
  1. Define diffusion? Explain the phenomenon of diffusion with an example.
  2. Gases take the shape of the container in which they are present. Comment? Give reason: “Gases have no fixed boundaries”
  3. Why does the temperature of a substance remain constant during its melting point or boiling point?
  4. Draw a labelled diagram of the experimental set up to demonstrate the sublimation of ammonium chloride?
  5. Explain an activity to show the factors affecting evaporation?




  1. Fill in the blanks:
  1. The mixture of metal are called______
  2. % strength by Mass = ___________
  3. A colloid is a ___________ mixture and its component can be separated by the technique is known as _______
  4. Ice, water and water vapour look different and display different __________ properties but they are ____ the same.
  5. The liquid which leaves behind a residue on heating is ______
  6. Pure liquid from a solution is obtained by ______
  7. A ____ shows the properties of constituent substances.
  8. New substances are formed in a _____ change.
  9. Air is a ____ of several gases
  10. Tyndall effects is produced by ______
  1. Multiple Choice Question
  1. Particles of which are visible by naked eyes:
  1. Mixture
  2. Colloidal solution
  3. Suspension
  4. None of these
  1. Most elements are:
  1. Solids
  2. Liquids
  3. Gases
  4. Mixtures
  1. Select the non-metal from the following:
  1. Diamond
  2. Gold
  3. Silver
  4. Platinum
  1. Select a colloidal solution out of the following.
  1. Gold ornaments
  2. Sand grains
  3. Lime water
  4. Paint
  1. Impure salt can be purified by the process:
  1. Fractional evaporation
  2. Distillation
  3. Fractional purification
  4. Crystallization
  1. Solution of soap in water is a:
  1. True solution
  2. Colloidal solution
  3. Suspension
  4. None of the above
  1. Write True or False
  1. A liquid mixture of carbon tetrachloride and water can be separated by separating funnel
  2. Sodium chloride undergoes sublimation.
  3. Air is a compound
  4. Iodine and sand can be separated by sublimation
  1. Short questions and answers
  1. Define aerosol?
  2. Differentiate between a solution and a mixture
  3. Define following terms:
  1. Ductility
  2. Malleability
  3. Brittleness
  1. What is meant by element and a compound
  2. Explain tyndall effect.
  1. Long Question and Answer
  1. Calculate the mass of sodium sulphate required to prepare its 20% (mass percent) solution in 100 g water?
  2.  Differentiate between colloid, suspension and solution
  3. Define filtration? Give any three example in which filtration proceed is used?
  4. Define distillation. Explain the principle of distillation
  5. Define magnetic separation. What is meant by sublimate? Define fractional crystallization.





  1. Fill in the Blanks
  1. The law of conservation of mass was proposed by ______ in _______
  2. The law of constant was proposed by _________ in ______
  3. The smallest particles of matter are_______
  4. The radius of an atom or the atomic radius is measured in _____
  5. _______ are the building blocks of all matter
  6. Alchemist were also called__________
  7. Atoms exist in the form of _________ and ________
  8. Atoms of the same elements or of different elements can join together to form ________
  9. Ions are also called as__________
  10. Formula of sodium carbonate is ________ and that of ammonium sulphate is ______
  1. Multiple Choice Questions
  1. Which among the following is not correctly matched?
  1. Copper – Co
  2. Cobalt- Co
  3. Calcium – Ca
  4. Silver- Ag
  1. A sample contains 22g of carbon dioxide. This is equal to:
  1. One molar volume of carbon dioxide
  2. One mole of carbon dioxide
  3. Half mole of carbon dioxide
  4. Two moles of carbon dioxide
  1. One amu means:
  1. Mass of hydrogen molecules
  2. Mass of C- 12 atoms
  3. 1/12th mass of C-12 atoms
  4. Mass of O- 16 atoms
  1. The value of Avogadro constant is:
  1. 6.022 x 1024
  2. 6.022 x 1022
  3. 6.022 x 1023
  4. 60.22 x 1023
  1. Kalium is the latin name of:
  1. Potassium
  2. Krypton
  3. Calcium
  4. Phosphorous
  1. The term ‘mole’ was introduced by:
  1. Lavoisier
  2. Dalton
  3. Ostwald
  4. Avogadro
  1. Write True or False
  1. Copper is diatomic
  2. A sulphide ion has positive charge
  3. The formula of calcium oxide is Ca2O2
  4. The law of definite proportions was proposed by Proust
  1. Short Questions and Answers
  1. Define chemical formula. Write down the chemical formula of (a) Hydrogen peroxide, (b) Zinc nitrate.
  2. Define molar mass. Give its unit
  3. Give the atomic mass of: (a) Magnesium (b) Calcium (c) Potassium?
  4. What are the drawbacks of Dalton’s atomic theory? Why Dalton’s atomic theory was accepted?
  5. Define law of constant proportion.
  1. Long Question and Answers
  1. Mention features of Dalton’s atomic theory.
  2. If the ratio by mass of magnesium and Sulphur is 3: 4 in magnesium sulphide, then what is the ratio of the number of magnesium and Sulphur atoms?
  3. Define formula unit of an ionic compound. Give the formula unit of sodium chloride and magnesium chloride.
  4. Define empirical formulae. How will you determine the empirical formulae?
  5. Differentiate between simple and compound ions. How will you calculate the formula mass of an ionic compound?










  1. Fill in the Blanks:
  1. The charge on the electron was determined by________
  2. The subatomic particles were regarded as the ____________
  3. The absolute charge of the proton is________
  4. Bohr model of atom was based on _______
  5. ________ rays are negatively charged
  6. The __________ fundamental sub atomic particles are negatively charged
  7. Anode _______ rays are also called.
  8. Mass of a proton is ________ times the mass of an electron
  9. ________ are atoms of the same element, which have same number of proton but different mass numbers.
  10. Atomic number is equal to_________
  1. Multiple choice Questions:
  1. The maximum number of electron that can be accommodated in M shell is:
  1. 2
  2. 8
  3. 18
  4. 32
  1. Protium, Deutrium and Tritium are isotopes of
  1. Rhodium
  2. Sodium
  3. Helium
  4. Hydrogen
  1. Number of neutrons presents in Hydrogen atom is:
  1. 0
  2. 2
  3. 1
  4. 3
  1. In an atom, the mass number of an atom is equal to the number of:
  1. Nucleons
  2. Proton
  3. Electrons
  4. Neutrons
  1. α – particles are:
  1. negative charged particles
  2. positive charged particles
  3. beam of neutrons
  4. gamma radiations
  1. proton was discovered by:
  1. Rutherford
  2. Goldstein
  3. Chadwick
  4. J.J. Thomson
  1. Write True or False
  1. The outermost shell is an atom have more than 8 electrons
  2. Electron are stationary in different energy shell.
  3. All atoms exist independently
  4. I-131 is effective in the treatment of cancer.
  1. Short Question and Answers
  1. What are canal rays?
  2. Differentiate between electron, proton and neutron
  3. Calculate the number of neutrons present in the nucleus of an elements X which is represented as 3115 X
  4. Why do Helium, Neon and Argon have a zero valency?
  5. Name the scientist and his experiments to prove that nucleus of an atom is positively charged?
  1. Long Question and Answers
  1. Describe Rutherford’s model of an atom.
  2. What are the isotopes of hydrogen? Give their symbols and name.
  3. Explain why the atomic masses of many elements are in fractions and not in which whole numbers?
  4. Explain the characteristics of cathode rays.
  5. What are the drawbacks of Rutherford’s model of an atom? What are the postulate of Bohr’s model of an atoms?












Important Links :

1) How to master Physics for IIT-JEE Class 11 and 12 Boards

2) Bye-Bye Exams by Dr. Sayantani Bhattacharjee

3) An Experts Speaks by Souravi Chakraborty

4) Class 10 CBSE Science Important questions

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  2019-11-24 08:42:17

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