Chemistry class 9thClass Matric Part 1 Notes

9th Class Chemistry Important Question

9th Class Chemistry All Chapter Important Question On Newsongoogle By Bilal Articles

Discover Class 9th Chemistry resources on Newsongoogle by Bilal Articles, including all-chapter notes, past papers, and guess papers. Strengthen your preparation with comprehensive materials tailored for success in exams. Elevate your understanding of chemistry concepts and excel in your Class 9th Chemistry studies with these valuable resources.

Chemistry Chapter 1 Matter in Our Surroundings Important Questions

Q1. A sample of water under study was found to boil at 102 ℃ at normal temperature and pressure. Is the water pure? Will this water freeze at 0 ℃? Comment.
Q2. A student heats a beaker containing ice and water. He measures the temperature of the content of the beaker as a function of time. Which of the following (Fig. 1.1) would correctly represent the result? Justify your choice.
Q5. Osmosis is a special kind of diffusion. Comment.
Q6. Classify the following into osmosis/diffusion
Q7. Water as ice has a cooling effect, whereas water as steam may cause severe burns. Explain these observations.
Q8. Alka was making tea in a kettle. Suddenly she felt intense heat from the puff of steam gushing out of the spout of the kettle. She wondered whether the temperature of the steam was higher than that of the water boiling in the kettle. Comment.
Q9. A glass tumbler containing hot water is kept in the freezer compartment of a refrigerator (temperature < 0 OC). If you could measure the temperature of the content of the tumbler, which of the following graphs
Q10. Look at Fig. 1.3 and suggest in which of the vessels A, B, C or D the rate of evaporation will be the highest? Explain.
Q11. (a) Conversion of solid to vapour is called sublimation. Name the term used to denote the conversion of vapour to solid.
(b) Conversion of solid-state to liquid state is called fusion; what is meant by the latent heat of fusion?

Chemistry Chapter 2 Matter in Our Surroundings Long Questions:

Q1. You are provided with a mixture of naphthalene and ammonium chloride by your teacher. Suggest an activity to separate them with a well-labelled diagram.
Q2. It is a hot summer day, Priyanshi and Ali are wearing cotton and nylon clothes respectively. Who do you think would be more comfortable and why?
Q3. You want to wear your favourite shirt to a party, but the problem is that it is still wet after a wash. What steps would you take to dry it faster?
Q4. Comment on the following statements:
Q5. Why does the temperature of a substance remain constant during its melting point or boiling point?

Fill in the blanks:

(a) Evaporation of a liquid at room temperature leads to a __ effect.

(b) At room temperature, the forces of attraction between the particles of solid substances are _ than those which exist in the gaseous state.

(c) The arrangement of particles is less ordered in the _ state. However, there is no order in the _ state.

(d) _ is the change of gaseous state directly to solid state without going through the state.

(e) The phenomenon of the change of a liquid into the gaseous state at any temperature below its boiling point is called _.

Chemistry Chapter 2 Is Matter Around Us Pure Important Questions with Answers

Q1. Suggest separation technique(s) one would need to employ to separate the following mixtures.
Q2. Which tubes in Fig. 2.1 (a) and (b) will be more effective as a condenser in the distillation apparatus?
Q3. Salt can be recovered from its solution by evaporation. Suggest some other technique for the same?
Q4. Seawater can be classified as a homogeneous and heterogeneous mixture. Comment.
Q5. While diluting a solution of salt in water, a student added acetone (boiling point 56°C) by mistake. What technique can be employed to get back the acetone? Justify your choice.
Q6. What would you observe when
Q7. Explain why particles of a colloidal solution do not settle down when left undisturbed, while they do in the case of a suspension.
Q8. Smoke and fog both are aerosols. In what way are they different?
Q9. Classify the following as physical or chemical properties
Q10. The teacher instructed three students, ‘A’, ‘B’ and C’, respectively, to prepare a 50% (mass by volume) sodium hydroxide (NaOH) solution. ‘A’ dissolved 50g of NaOH in 100 mL of water, ‘B’ dissolved 50g of NaH in 100g of water while C’ dissolved 50g of NaOH in water to make 100 mL of solution. Which one of them has made the desired solution and why?
Q11. Name the process associated with the following
Q12. You are given two water samples labelled as ‘A’ and ‘B’. Sample ‘A’ boils at 100°C, and sample “B’ boils at 102°C. Which sample of the water will not freeze at 0°C? Comment.
Q13. What are the favourable qualities given to gold when it is alloyed with copper or silver to make omaments?
Q14. An element is sonorous and highly ductile. Under which category would you classify this element? What other characteristics do you expect the element to possess?
Q15. Give an example of each mixture having the following features. Suggest a suitable method to separate the components of these mixtures.

Q16. Fill in the blanks

(a) A colloid is a _ mixture whose components can be separated by the technique known as _.

(b) Ice, water and water vapour look different and display different properties but are _ the same.

(c) A mixture of chloroform and water is taken in a separating funnel is mixed and left undisturbed for some time. The upper layer in the separating funnel will be of _, and the lower layer will be that of _.

(d) A mixture of two or more miscible liquids, for which the difference in the boiling points is less than 25 K, can be separated by the process called _.

(e) When light is passed through water containing a few drops of milk, it shows a bluish tinge. This is due to the _ of light by milk, and the phenomenon is called . This indicates that milk is a __ solution.

Q17. Sucrose (sugar) crystals obtained from sugarcane and beétroot are mixed together. Will it be a pure substance or a mixture? Give reasons for the same.
Q18. Give some examples of Tyndall effect observed in your surroundings?
Q19. Can we separate alcohol dissolved in water by using a separating funnel? If yes, then describe the procedure. If not, explain.
Q20. On heating, calcium carbonate gets converted into calcium oxide and carbon dioxide.
Q21. Non-metals are usually poor conductors of heat and electricity. They are non-lustrous, non-sonorous, non-malleable and are coloured.
Q22. Classify the substances given in Fig. 2.2 into elements and compounds
Q23. Which of the following are not compounds?

Chemistry Chapter 2 Is Matter Around Us Pure Long Questions

Q1. Fractional distillation is suitable for separating miscible liquids with a boiling point difference of about 25 K or less. What part of the fractional distillation apparatus makes it efficient and possesses an advantage over a simple distillation process. Explain using a diagram.
Q2. (a) Under which category of mixtures will you classify alloys and why?
(b) A solution is always a liquid. Comment.
(c) Can a solution be heterogeneous?
Q3. Iron filings and sulphur were mixed together and divided into two parts, ‘A’ and ‘B’. Part ‘A’ was heated strongly while Part ‘B’ was not heated. Dilute hydrochloric acid was added to both the Parts and the evolution of gas was seen in both the cases. How will you identify the gases evolved?
Q4. A child wanted to separate the mixture of dyes constituting an ink sample. He marked a line by the ink on the filter paper and placed the filter paper in a glass containing water, as shown in Fig. 2.3. The filter paper was removed when the water moved near the top of the filter paper.
Q5. A group of students took an old shoe box and covered it with a black paper from all sides. They fixed a source of light (a torch) at one end of the box by making a hole in it and made another hole on the other side to view the light. They placed a milk sample contained in a beaker/tumbler in the box as shown in the Fig.2.4. They were amazed to see that milk taken in the tumbler was illuminated. They tried the same activity by taking a salt solution but found that light simply passed through it?
Q6. Classify each of the following, as a physical or a chemical change. Give reasons.
Q7. The students were asked to prepare a 10% (Mass / Mass) sugar solution in water during an experiment. Ramesh dissolved 10 g of sugar in 100 g of water while Sarika prepared it by dissolving 10 g of sugar in water to make 100 g of the solution.
(a) Are the two solutions of the same concentration
(b) Compare the mass % of the two solutions.
Q8. You are provided with a mixture containing sand, iron filings, ammonium chloride and sodium chloride. Describe the procedures you would use to separate these constituents from the mixture?
Q9. Arun has prepared a 0.01 % (by mass) sodium chloride solution in water. Which of the following correctly represents the composition of the solutions?
Q10. Calculate the mass of sodium sulphate required to prepare its 20 % (mass per cent) solution in 100g of water?

Chemistry Chapter 3 Atoms and Molecules Important Questions:

Q1. Which of the following represents a correct chemical formula? Name it.
Q2. Write the molecular formulae for the following compounds
Q3. Write the molecular formulae of all the compounds that can be formed by the combination of the following ions. Cu2+, Na+, Fe3+, Cl–, SO42-, PO43-.
Q4. Write the cations and anions present (if any) in the following compounds
Q5. Give the formulae of the compounds formed from the following sets of elements
Q6. Which of the following symbols of elements are incorrect? Give their correct symbols
Q7. Give the chemical formulae for the following compounds and compute the ratio by mass of the combining elements in each one of them. (You may use appendix-III).
Q8. State the number of atoms present in each of the following chemical species
Q9. What is the fraction of the mass of water due to neutrons?
Q10. Does the solubility of a substance change with temperature? Explain with the help of an example.
Q11. Classify each of the following based on their atomicity.
Q12. You are provided with a fine white coloured powder, either sugar or salt. How would you identify it without tasting it?
Q13. Calculate the number of moles of magnesium present in a magnesium ribbon weighing 12 g. The molar atomic mass of magnesium is 24g mol-1.

Chemistry Chapter 3 Atoms and Molecules Long Questions

Q1. Verify by calculating that
Q2. Find the ratio by mass of the combining elements in the following compounds. (You may use Appendix-III)
Q3. When dissolved in water, calcium chloride dissociates into its ions according to the following equation.
Calculate the number of ions obtained from CaCl2 when 222 g of it is dissolved in water.
Q4. The difference in the mass of 100 moles of sodium atoms and sodium ions is 5.48002 g. Compute the mass of an electron.
Q5. Cinnabar (HgS) is a prominent ore of mercury. How many grams of mercury are present in 225 g of pure HgS? The molar mass of Hg and S is 200.6 g mol-1 and 32 g mol-1, respectively.
Q6. The mass of one steel screw is 4.11g. Find the mass of one mole of these steel screws. Compare this value with the mass of the Earth (5.98 × 1024 kg). Which one of the two is heavier, and by how many times?
Q7. A sample of vitamin C is known to contain 2.58 x1024 oxygen atoms. How many moles of oxygen atoms are present in the sample?
Q8. Raunak took 5 moles of carbon atoms in a container, and Krish took 5 moles of sodium atoms in another container of the same weight. (a) Whose container is heavier? (b) Whose container has more number of atoms?
Q10. The visible universe is estimated to contain 1022 stars. How many moles of stars are present in the visible universe?
Q11. What is the SI prefix for each of the following multiples and submultiples of a unit?
Q12. Express each of the following in kilograms
Q13. Compute the difference in masses of 103 moles each of magnesium atoms and magnesium ions. (Mass of an electron = 9.1 x 10-31 kg)
Q14. Which has more number of atoms?
100g of N2 or 100 g of NH3.
Q15. Compute the number of ions present in 5.85 g of sodium chloride.
Q16. A gold sample contains 90% of gold and the rest copper. How many atoms of gold are present in one gram of this sample of gold?
Q17. What are ionic and molecular compounds? Give examples.
Q18. Compute the difference in masses of one mole of aluminium atoms and one mole of its ions. (Mass of an electron is 9.1 × 10-28 g). Which one is heavier?
Q19. A silver ornament of mass ‘m’ gram is polished with gold equivalent to 1% of the mass of silver. Compute the ratio of the number of atoms of gold and silver in the ornament.
Q20. The ethane (C2H6) gas sample has the same mass as 1.5 x1020 molecules of methane (CH4). How many C2H6 molecules does the sample of gas contain?

Q21. Fill in the blanks

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

(b) A group of atoms carrying a fixed charge on them is called __

(c) The formula unit mass of Cag(PO4)2 is _

(d) Formula of sodium carbonate is , and that of ammonium sulphate is

Q22. Complete the following crossword puzzle (Fig. 3.1) by using the name of the chemical elements. Use the data given in Table 3.2.
Q23. (a) In this crossword puzzle (Fig 3.2), the names of 11 elements are hidden. Symbols of these are given below. Complete the puzzle.
Q24. Write the formulae for the following and calculate the molecular mass for each of them.
Q25. In photosynthesis, six molecules of carbon dioxide combine with an equal number of water molecules through a complex series of reactions to give a molecule of glucose having a molecular formula C6H12O6. How many grams of water would produce 18 g of glucose? Compute the volume of water consumed, assuming the density of water to be 1g cm-3.

Chemistry Chapter 4 Structure of the Atom Important Questions

Q1: Is it possible for the atom of an element to have one electron, one proton and no neutron. If so, name the element.
Q2: Write any two observations which support the fact that atoms are divisible.
Q3: Will 35Cl and 37Cl have different valencies? Justify your answer.
Q4: Why did Rutherford select a gold foil in his α–ray scattering experiment?
Q5: Find out the valency of the atoms represented by the Fig. 4.3 (a) and (b).
Q6: One electron is present in the outer most shell of the atom of an element X. What would be the nature and value of charge on the ion formed if this electron is removed from the outer most shell?
Q7: Write down the electron distribution of chlorine atom. How many electrons are there in the L shell? (Atomic number of chlorine is 17).
Q8: In the atom of an element X, 6 electrons are present in the outermost shell. If it acquires noble gas configuration by accepting requisite number of electrons, then what would be the charge on the ion so formed?
Q9: What information do you get from the Fig. 4.4 about the atomic number, mass number and valency of atoms X, Y and Z? Give your answer in a tabular form.
Q10: In response to a question, a student stated that in an atom, the number of protons is greater than the number of neutrons, which in turn is greater than the number of electrons. Do you agree with the statement? Justify your answer.
Q11: Calculate the number of neutrons present in the nucleus of an element X which is represented as 31X15.
Q12: Match the names of the Scientists given in column A with their contributions towards the understanding of the atomic structure as given in column B.
Q13: The atomic number of calcium and argon are 20 and 18 respectively, but the mass number of both these elements is 40. What is the name given to such a pair of elements?
Q14: Complete Table 4.1 on the basis of information available in the symbols given below.
Q15: Helium atom has 2 electrons in its valence shell but its valency is not 2, Explain.

Q16: Fill in the blanks in the following statements:

(a) Rutherford’s α-particle scattering experiment led to the discovery of the _.

(b) Isotopes have same but different______.

(c) Neon and chlorine have atomic numbers 10 and 17 respectively. Their valencies will be and _ respectively.

(d) The electronic configuration of silicon is and that of sulphur is _.

Q17: An element X has a mass number 4 and atomic number 2. Write the valency of this element.

Chemistry Chapter 4 Structure of the Atom Long Questions:

Q1: Why do Helium, Neon and Argon have a zero valency?
Q2: The ratio of the radii of hydrogen atom and its nucleus is ~ 105. Assuming the atom and the nucleus to be spherical,
Q3: Enlist the conclusions drawn by Rutherford from his α-ray scattering experiment.
Q4: In what way is the Rutherford’s atomic model different from that of Thomson’s atomic model?
Q5: What were the drawbacks of Rutherford’s model of an atom?
Q6: What are the postulates of Bohr’s model of an atom?
Q7: Show diagrammatically the electron distributions in a sodium atom and a sodium ion and also give their atomic number.
Q8: In the Gold foil experiment of Geiger and Marsden, that paved the way for Rutherford’s model of an atom, ~ 1.00% of the α-particles were found to deflect at angles > 50°. If one mole of α-particles were bombarded on the gold foil, compute the number of α-particles that would deflect at angles less than 50°.

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