9th Class Chemistry Guess Paper 2021 Lahore Board

9th Chemistry Guess Lahore Board


Questions # 1

  • Give two properties of neutrons.
  • How many neutrons are present in C-12 and C-13?
  • Do you know any element having no neutrons in its atoms?

Questions # 2

  • Why the second ionization energy of an element is higher than first one?
  • What do you mean by blocks in a periodic table and why elements were placed in blocks?
  • For an element Z = 92, A = 238. Calculate the number of electron and proton in it.
  • What is the definition of the element according to the Robert Boyle?
  • What is the significance of the symbol of an element?
  • Define Boyle’s Law and verify with an example.
  • What type of elements from metallic bond?
  • Define Avogadro’s number.
  • Which element has the highest electro negativity?
  • What type of elements have tendency of sharing of electrons?
  • Why and how elements arranged in a period?
  • What type of elements are metals?
  • Write down the names of elements of group 1 with their symbols?
  • Define Boyle’s rule?

Questions # 3

  • Write two chemical properties of metals and non-metals.
  • Define metal, give two examples.
  • Write down the name of four least reactive metals.
  • Compare any four physical properties of metals and non-metals.
  • What are important physical characteristics of metals?
  • Why reactivity of metals increase drown the group?
  • How non-metals are essential part of our body structure?
  • Which metal is used for metal work?
  • State the physical properties of metals
  • What is the trend of variation it densities of alkali metals?
  • Metals are good conductor of electricity. Why?
  • What are transition metals?
  • How oxygen reacts with group II A metals?

Questions # 4

  • Why silver and gold are least reactive?
  • Give properties and uses of gold?
  • Which is lighter than aluminum of gold?
  • Give the applications of silver. Why platinum is used for making Jewellery?
  • Can pure gold be used for making electrical wires?

Questions # 5

  • Give the Properties of dipole-dipole forces.
  • Define dipole interactions. How are they created?

Questions # 6

  • Write down any two properties of canal rays.
  • Give two properties of positive rays.
  • Write down two properties, of cathode rays.
  • What conclusion you derive from these properties.
  • How are cathode rays produced?
  • What is the nature of charge on cathode rays?
  • What are its five major characteristics?

Questions # 7

  • Define atomic mass unit. Why is it needed?
  • Define atomic number and mass number.
  • What are SI units of atomic radius?
  • Define Tri-atomic and Hetero-atomic.
  • Why do atoms react?
  • How can you define atomic radius?
  • What is Luther Meyer’s atomic volume curve?
  • What is meant by atomic size? Write its unit.
  • What are the salient features of Rutherford’s atomic model?
  • How Rutherford discovered that atom has a nucleus located at the centre of the atom?
  • What are the defects of Rutherford atomic model?
  • Give two postulates of Bohr’s atomic theory.
  • How it is related to gram?
  • What is the relative atomic mass?
  • Find out the mass of 3 moles of oxygen atoms.
  • Why the size of atom decreases in a period?
  • How to atoms follow octet rule?
  • What is trend of atomic radius in period and group?
  • Calculate the number of atoms in 10 grams of Aluminum (Al).
  • Differentiate between Homo atomic and Hetero atomic molecules.
  • How is periodicity of properties dependent upon number of protons in an atom?
  • Calculate the number of moles, number of molecule atoms present in 6 grams of water.
  • How was it proved that electrons are fundamental particles of an atom?
  • Give basic postulates of Bohr’s atomic theory.
  • Give the electronic configuration of carbon atom.

Questions # 8

  • Give the physical properties of sodium and its uses.
  • Write any two uses of sodium.
  • Why does sodium make ionic bond with chlorine?
  • Why does sodium forma chemical bound with chloride?
  • Why magnesium is harder than sodium.

Questions # 9

  • Write down two uses of calcium.
  • Give physical properties of calcium and its uses.
  • Why calcium is more electropositive tan to magnesium?
  • Write the chemical formulae of Aluminium Sulphate and Calcium Phosphate.

Questions # 10

  • Define and explain Charles’s Law of gasses.
  • Whether the density of gases increases on cooling? Explain.
  • Why are the densities of gases lower than that of liquids?
  • Why the gases are compressible?
  • Why noble gases are not reactive?
  • Can you cool a gas by increasing it volume?

Questions # 11

  • What is meant by volume / volume %?
  • What do you mean by %-mass / mass?
  • Give the example and formula of mass by volume percent.
  • There are 3.01 x 1023 molecules of CO2 present in a container.
  • Calculate the number of moles of coal in the given mass.
  • Calculate the number of moles and its mass. You have a piece of coal (carbon) weighing 9.0 grams.
  • How can you differentiate between molecular formula, formula mass and empirical formula?
  • Calculate the number of moles of coal in the given mass.

Questions # 12

  • Briefly describe its principle, purpose and procedure.
  • Define electroplating.
  • What are non-electrolytes, give example?
  • How electroplating of tin on steel carried out?
  • How electroplating of zinc is carried out?
  • In electroplating of chromium, which salt is used as an electrolyte?
  • Which solution is used as electrolyte in Nelson’s cell?
  • Differentiate between strong and weak electrolytes.

Questions # 13

  • Define Galvanic cell.
  • What is salt bridge?
  • How the half cells of galvanic cell are connected?
  • What is the difference between anode and cathode?
  • What happens to cathode in the galvanic cell?
  • What is the function of salt bridge?
  • Write two differences between electrolytic and galvanic cell.

Questions # 14

  • What do you mean by groups and periods in the periodic table?
  • What do you mean by periodic function?
  • What are the Defects in Long Form of Periodic Table?
  • Define electron affinity.
  • Explain the trend of electron affinity in periodic table.
  • Describe its trend in periodic table.
  • What do you mean by shielding effect?
  • Discuss the important features of modern periodic table.
  • Explain its trends in periodic table.
  • Describe its trend in the periodic table.
  • What is the difference between Mendeleev’s periodic law and modern periodic law?
  • What are Halogens? Describe the position of halogen in periodic table?

Questions # 15

  • Explain the term oxidation on the basis, of electrons concept with an example.
  • Define valiancy.
  • Describe oxidation and reduction in term of loss or gain of electron.
  • What is the oxidation number Carbon in Na2CO3?
  • Calculate oxidation number of nitrogen in HNO3.
  • What is reduction?
  • Explain with an example. Describe the rules for assigning the oxidation state.
  • Oxidation and reduction proceed simultaneously.
  • What is difference between valiancy and oxidation state?
  • Explain the term oxidation on the basis of electronic concept with an example.

Questions # 16

  • Write down general electronic configuration of carbon family.
  • Write down the electronic configuration of chloride ion.
  • Write down the electronic configuration of Na.
  • Write down electronic configuration of chlorine.
  • Write down the electronic configuration of Be and Ne.

Questions # 17

  • What is the maximum capacity of a shell?
  • Differentiate between shell and subshell.

Questions # 18

  • A solution contains 50 g of sugar dissolved in 450 g of water.
  • What is the unit of concentration?
  • What is concentration of this solution?

Questions # 19

  • What is meant by carbon dating?
  • What is mole? Calculate the number of moles In 84 gram carbon.

Questions # 20

  • Define chemical bond.
  • What is meant by metric bond?
  • Differentiate between lone pair and bond pair of electrons.
  • Differentiate between Polar and non polar covalent bond.
  • Describe at least two necessary conditions for the formation of a covalent bond.
  • How coordinate covalent bond is formed in the hydronium ion?
  • What is the cause of polarity in covalent bond?
  • What type of covalent bond is formed in nitrogen molecule?
  • Why have water polar covalent bonds?
  • Define ionic bond, explain different steps in the formation of NaCr.
  • What is a triple covalent bond, explain with an example?
  • What is a coordinate covalent bond? Explain it with example.
  • What is metallic bond? Explain the metallic bonding with the help of a diagram.
  • Explain double covalent bond with the help of an example.
  • Define hydrogen bonding. Explain how these properties affect the physical properties of compound.
  • Define ionic bond and Why ionic compounds are easily soluble in water?
  • Define coordinate covalent bond. How it is formed. Explain with examples.

Questions # 21

  • Differentiate between Oxidizing agents and Reducing agents with the help of an example.
  • Define reducing agent.

Questions # 22

  • Which form of sculpture exists at room temperature?
  • Define transition temperature.
  • What is absolute temperature?
  • What is general principle of solubility?
  • What is absolute zero temperature?
  • What is the effect of temperature on solubility?
  • Define pressure and write its unit.
  • What is vapor pressure and how it is affected by intermolecular forces?
  • Why is vapour pressure higher at high temperature?
  • Define atmospheric pressure.

Questions # 23

  • Briefly describe the electrolysis of water.
  • What is electrolysis?
  • Describe the process that take place in the electrolysis of molten NaCI.

Questions # 24

  • How can distinguish between solution and pure solvent?
  • How you can explain the solute-solvent interaction to prepare a NaCl solution?
  • Define solute and solvent.
  • Differentiate between solute and solvent with examples of each.

Questions # 25

  • Define aqueous solution.
  • What does mean by unsaturated solution?
  • Define super saturated solution When we dissolve 20 g of NaC1 in 400 cm3 of solution, what will be its molarity?
  • What is molarity and give its formula to prepare molar solution?
  • How much NaOH is required to prepare 500cm3 of 0.4M solution?
  • What is the major difference between a solution and a mixture?
  • Describe different ways of expressing the percentage composition of a solution.
  • Describe Nelson’s Cell for the manufacture of Caustic soda from brine solution.
  • What is meant by Molar Solution? How it is prepared.
  • Compare the characteristics of solution, colloid and suspension.
  • Why a solution is considered mixture?
  • Differentiate between dilute solution and concentrated solutions with a common example.
  • Why the alloys are considered solutions?

Questions # 26

  • Define electron electivity.
  • Define electro chemistry.
  • How electro negativity does differ from electron affinity?
  • What is electro negativity?
  • What is the relationship between electro positively and ionization energy?
  • What is relationship between electro negativity and polarity?
  • Describe the trends of electro negativity in a period and in a group.

Questions # 27

  • Why chlorine can accept only 1 electron?
  • When does an electron emit or absorb energy?

Questions # 28

  • What are synthetic adhesives?
  • What you know about Epoxy adhesives?

Questions # 29

  • Write any five characteristics of mixture.
  • What is meant by mixture?
  • State the reason soft drink is a mixture and water is a compound.
  • Why does ice float on water?
  • Find out the molecules in 9 gram of water.
  • State any three difference between compound and mixture.
  • How does homogeneous mixture differ from heterogeneous mixture?
  • State three reasons why do you think air is a mixture and water a compound.
  • Why does not the suspension form homogeneous mixture?

Questions # 30

  • Describe the phenomenon of diffusion in liquids along the factors which influence it.
  • Define diffusion.
  • What is difference between diffusion and effusion?
  • Describe the factors which influence the diffusion of liquid.

Questions # 31

  • Write the name of factors which effect evaporation.
  • Define evaporation.
  • What do you mean by evaporation, how it is affected by surface area?
  • What is difference between boiling point and evaporation?
  • What is the relationship between evaporation and boiling point of liquid?
  • Evaporation causes cooling. Explain.

Questions # 32

  • What did you mean by the Thermal conductivity of the metallic compounds?
  • What do you mean by metallic character?

Questions # 33

  • How can a non-spontaneous reaction be carried out in an electrolytic cell? Discuss in detail.
  • What are spontaneous and non spontaneous reactions?

Questions # 34

  • Distinguish between amorphous solid and crystalline solid.
  • Define crystalline solid and give its two examples.

Questions # 35

  • What is difference between colloids and suspensions?
  • How can you justify the milk is colloid?
  • Why are the colloids quite stable?
  • What is meant by colloid? Give two examples.

Questions # 36

  • Why are liquids mobile?
  • Write two properties of liquids.

Questions # 37

  • Write four properties of covalent compounds.
  • What are ionic and covalent compounds?
  • Ionic compounds are solids justify.
  • Write two properties of solids.

Questions # 38

  • Give the trend of ionization energy in a period.
  • Define Ionization energy.
  • Why ionization energy Na is less than Mg?
  • Why the ionization energy of Na more than K?
  • What is second ionization energy and how is it represented?

Questions # 39

  • What are radioactive isotopes?
  • Write isotopes of chlorine.
  • Give one example each of the use of radioactive isotope in medicine and radio therapy.
  • Describe some major applications of radioactive isotopes in our surroundings.
  • Write down any three isotopes of uranium.
  • What is isotope? Discuss the structure of Isotope with suitable examples.
  • Give the applications of isotopes in the field of radiotherapy and medicines.
  • Describe the isotope of hydrogen with diagram.
  • What is an isotope?

Questions # 40

  • Write at least two physical properties of magnesium.
  • What is meant by magnesium ribbon and where it use?
  • Write down any two uses of magnesium.

Questions # 41

  • Briefly describe the electrolytic refining of copper.
  • What is electrolytic cell briefly describe its construction and working?
  • Give the difference between electrolytic cell electro chemical cells.

Questions # 42

  • What is inolarity? Write its formula.
  • Describe the significance of chemical formula.

Questions # 43

  • Write different types of molecules What is the difference molecule and molecular ion?
  • What is a molecule?

Questions # 44

  • Write a note on the construction of a Daniel Cell.
  • Briefly describe the construction and working of Daniel cell?

Questions # 45

  • Write any two chemical properties of halogens.
  • Write down the important chemical reactions of halogens.

Questions # 46

  • Why we stir paints thoroughly before using?
  • Define substance. Mole is SI unit for the amount of a substance. Define it with examples.
  • Define boiling point and also explain the factors which are affected on it?
  • Explain classical theory of radiation
  • Discuss the construction and working of a cell in which electricity is produced.
  • Write a short note on Allotropy.
  • Describe the classification of Dobereiner’s triads and give one example.
  • What do you mean by cation and anion? Explain with examples.
  • What are redox reactions?
  • Give chemical reaction between methane (CH4) and chlorine (Ct2 ) in the presence of diffused light.
  • Write the names of Electro chemical cells.
  • Complete and balance the given chemical equation Na+H2
  • Define analytical chemistry.
  • Differentiate between periods and groups.
  • Define empirical forthula with example.
  • What is Metalloid?
  • What is matter?
  • Ionic compounds form solids. Justify.
  • What do you mean by dynamic equilibrium?
  • What do you mean by Pascal? How many Pascals are equal to I atm.
  • What do you mean by solubility?
  • What is meant by density?
  • What is suspension?
  • What is meant by condensation?
  • What is meant by Brine?
  • What is meant by chemical reactivity?
  • What is Lewi’s Structure Diagram?
  • What is % v/m ?
  • What is electro positivity? Explain with an example.
  • Define industrial chemistry.
  • Define bio chemistry and give the scope of bio chemistry.
  • Define physical chemistry.
  • How can you differentiate between organic and inorganic chemistry?
  • For what purpose is u-235 used?
  • Explain ductile.
  • Give experimental verification of Charles’s law.
  • Define oxidizing agent.
  • Define quantum theory.
  • Define symbol and valency with example. What is meant by variable valency?
  • Define homoatomic and hetroatomic morecule with examples.
  • Define freezing point.
  • Define malleable.
  • Define effective nuclear charge.
  • Define morality and writes its unit.
  • Define nuclear fission reaction
  • A patient has goiter. How will it be detected?
  • Define Nuclear Chemistry.
  • What is the difference between ions and free radicals?
  • Write the definition of Duplet rule and Octet role.
  • What is the nature of electrode used in electrolyzing of chromium?
  • What is meant by periodicity of properties?
  • What is difference between steel and stainless steel?
  • Define Alkali metals and Alkaline earth metals.
  • What is Dielectric Constant?
  • What are intermolecular forces?
  • Explain the term absolute zero.
  • Name the by-products produced in Down’s cell.
  • Why an iron grill is pointed frequently?
  • How can you prove that angular momentum is quantized?
  • Why is HF a weak acid?
  • Why do you mean by malleability?


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