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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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