Chapter 1 : Matter in our surroundings
1. A student adds 5 g sugar in 100 mL water. The student stirs the contents for 2 minutes. After some time, the student notices a clear solution. Why the student was unable to see sugar particles?
(a)they are colorless
(b)they settle at the bottom
(c)they are too small to be seen
(d)they evaporate when added to water
2. A student pours 20 mL flavored water in a glass containing plain water and notices that the taste of the water changes. The students repeat the activity for 10 times and reports that the water still has some flavor. What can be the possible reason for this?
(a)The flavor from the water
(b)The water is made flavored in such a way that it remains the same until it is consumed.
(c) Sieves were not used in the experiment which would have helped to remove flavored particles from the water.
(d) The particles of flavored water are very small and are transferred to plain water even when added in very small quantities.
3.A student adds ink to water. The ink particles spread throughout the water. Which property of water allows other particles to diffuse in it?
(a)fixed volume (b)inability to compress (c) intermolecular spaces (d) ability to change shape
4 A student put an equal amount of potassium permanganate powder over a glass plate and in a beaker filled with water. The student rubbed the surface of the plate and stir the contents of the beaker. It was observed that the permanganate powder dissolved in the water and formed a colored solution. Which option explains the reason for the student’s observation?
(a)Water is a liquid and can dissolve and solid particles in it
(b)The ability of water to exist in any state allows it to dissolve any substance
(c)Water has large intermolecular spaces which allow molecules of other substances to get between those spaces
(d)Water particles are tightly arranged in an orderly fashion which allows the binding of the molecules of other substances
5. A student learns that the speed of the formation of a solution increases when the heat is supplied. How does heat affect the formation of the solution?
(a)change in temperature increases the size of the water particles
(b)change in temperature changes the shape of the water particles
(c)change in temperature changes the kinetic energy of the particles
(d)change in temperature decreases the intermolecular spaces between the particles
6. A student puts one drop of food colour in 100 mL of water. The student notices that the food colour gradually spreads in the water. What is the possible reason for this phenomenon?
(a)a close arrangement of the water particles
(b)the ability of the water particles to move continuously
(c)the ability of the water to stay warm at room temperature
(d)small intermolecular space between the water particle
7. Why does an ice cube melt when put out of the refrigerator?
(a) because it loses heat and its particles move faster and farther causing melting
(b) because it loses heat and its particles gain kinetic energy changing from solid to liquid
(c) because it gains heat and its particles come closer since the force of attraction increases
(d) because it gains heat and its particles start moving faster and overcome the force of attraction
8. The melting point of ice is 0°C. At this temperature, both ice and water exist. However, the particles of water at 0°C have more energy than particles of ice at 0°C. What explains this?
(a) at melting point, water particles absorb more heat and change into ice
(b) at melting point, ice particles raise their temperature and change to water
(c) at melting point, water particles raise their temperature and change into ice
(d) at melting point, ice particles absorb latent heat and change into water particles
10.When ice is given heat, it reaches a temperature of 0°C and starts melting. The more heat is gained, the more it changes to water. However, the temperature remains constant at 0°C until all ice changes to water. Why does the temperature remain constant?
(a) because of the latent heat of fusion
(b) because of the kinetic energy of ice particles
(c) because of the latent heat of vaporization
(d) because of the kinetic energy of water particles
11. Which is not a common characteristic property of matter?
(a) The molecules possess kinetic energy
(b) The molecules occupy certain volume
(c) The molecules are rigid and have fixed positions
(d) The molecules vibrate between the mean positions
12. Which of the following gases can be liquefied when pressure is
applied at room temperature?
(a) Oxygen
(b) Ammonia
(c) Hydrogen
(d) Nitrogen
13. In
which of the following substances the molecules possess maximum kinetic energy
under normal conditions?
(a) Sugar
(b) Sulphur
powder
(c) Ammonium
Chloride
(d) Common Salt
14. When common salt is added
to water, its boiling point increases by 20℃. What would
be the boiling point of that salt water in Kelvin scale?
(a) 393 K
(b) 273 K
(c) 373 K
(d) 120 K
15.
Substances which occupy the entire space in the container under normal
conditions is _______
(i) Ammonia
(ii) Bromine
(iii) Iodine
(iv) Chlorine
(a) i, ii, iv (b) ii, iii
(c) iii only (d) i, iv
16. The
boiling point of alcohol is 78℃ and
its freezing point is – 114℃.
At what temperature does alcohol undergo evaporation?
(a) 124 K
(b) 159K
(c) 321 K
(d) 373 K
17.
Identify amorphous solid among the following.
(a) Charcoal
(b) Alum
(c) Common salt
(d) Graphite
18. What is
the phenomenon involved in a lawn becoming wet in the morning during winter?
(a)
Vaporisation
(b)
Liquefaction
(c)
Condensation
(d) Deposition
19. Which
of the following statements is correct?
Statement I: An
iron rod undergoes expansion on heating.
Statement Il: Solids show maximum thermal expansion.
(a) Only
statement I is correct
(b) Only
statement Il is correct
(c) Both the
statements are correct
(d) Neither statement I nor statement Il is correct
20.
Identify the water temperature which gets cooled at the maximum rate?
(a) Water at
100℃
(b) Water at 80℃
(c) Water at 70℃
(d) Water at 50℃
21. A
solid having a melting point of 325℃ is
subjected to heating. Which Statement is true which comply with this Solid?
(i) The kinetic
energy of the molecules increases continuously till the liquid state at 598 K
is obtained.
(ii) The solid
melts if it is heated up to 598 K and stopped.
(iii) The
molecules of molten solid possess greater amounts of energy than the solid at
the same temperature.
(iv) Heating the solid at room temperature supplies latent heat of fusion for the solid to undergo melting.
(a) i, ii, iii and iv (b) iii, iv
(c) i, iv (d) iii only
22. Which
substance has the most ordered arrangement of molecules under normal
conditions?
(a) Chlorine (b) Mercury (c) Gold (d) Bromine
23. Gases
do not have __________.
(a) high
compressibility
(b) large
volume
(c) high
fluidity
(d) high
density
24. A
solid is subjected to heating. The molecules formed were immediately diffused
into air. It concludes that
(a) the solid
has maximum forces of attraction between the molecules.
(b) the melting
point of the solid is close to room temperature.
(c) the solid is a sublimable substance.
Short answer
type questions :
Question: After removing
the lid separating them, what will be the composition in each jar after a few
minutes? Explain the molecular behavior leading to this outcome.
Question: If three vessels A, B, and C contain water
with kinetic energies EA > EB > EC,
arrange their temperatures TA, TB, and TC in
increasing order.
Question: A substance has high compressibility and
can take the shape of any container. Identify its state and justify your
answer.
Question: Why does sprinkling water on rooftops
during summer help in cooling the surroundings?
Question: A substance has high compressibility and
can take the shape of any container. Identify its state and justify your answer
Assignment 2" Matter in our surroundings
Ques : Assertion (A): Gaseous state of ammonia is not regarded as vapours.
Reason (R): As the volume of a substance increases, its density increases.
a) Both A and R are true and R is the correct explanation of A.
b) Both A and R are true but R is not the correct explanation of A.
c) A is true but R is false.
d) A is false but R is true.
Ques :When heat is constantly supplied by a gas burner to boiling water, then the temperature of water, during vapourisation
(a) rises slowly.
(b) does not rise at all.
(c) rises until steam is produced.
(d) rises and then becomes constant.
Ques :The property to flow is unique to fluids. Which one of the following statement is correct?
a. Only gases behave like fluids
b. Gases and solids behave like fluids
c. Gases and liquid behave like fluids
d. Only liquid are fluids
Ques : Why do we feel comfortable under a fan when we are perspiring?
Ques : Name A, B, C, D, E and F in the following diagram showing change in its state.
Ques : Which gas is called dry ice? Why?
OR
Suppose you want to convert a gas into a liquid, which two methods can you apply?
Ques : Explain why:
(i) Wet clothes dry quickly in the sun than in shade.
(ii) Trees acquire more leaves during summer.
(iii) We feel comfortable under a fan when we are perspiring.
Ques :Why do the gases exert more pressure on the walls of the container than the solids ?
OR
Which of the following diffuses faster ?
Water vapour, wax or, ethyl alcohol.
Chapter 2 " Is Matter Around us Pure?
Ques : Classify each of the following as a physical or a chemical change. Give reasons.
i. Drying of a shirt in the sun.
ii. Rising of hot air over a radiator.
iii. Burning of kerosene in a lantern.
iv. Change in the colour of black tea on adding lemon juice to it. v. Churning of milk cream to get butter.
Ques: Which of the following is homogeneous in nature?
(i) Ice (ii) Wood (iii) Soil (iv) Air
Ques : Rutherford’s alpha particle scattering experiment was responsible for the discovery of:
(a) Atomic Nucleus (b) Electron (c) Proton (d) Neutron
Ques : When iron and sulphur are heated at high temperature
a. Black coloured FeS is formed
b. Mixture of iron and sulphur is obtained
c. Yellow coloured iron sulphide is formed
d. They don’t heat
Chapter 3 " Atoms and Molecules
Ques : Match the following with the correct response:
(1) Nitrate (A) P3−
(2) Phosphide (B) PO43−
(3) Nitrite (C) NO2−
(4) Phosphate (D) NO3−
a) 1-B, 2-D, 3-A, 4-C
b) 1-C, 2-B, 3-D, 4-A
c) 1-D, 2-A, 3-C, 4-B
d) 1-A, 2-C, 3-B, 4-D
Ques : Modern atomic symbols are based on the method proposed by
(a) Dalton (b) Berzelius (c) Bohr (d) Mendeleev
Ques : Write the chemical formula of the following:
(a) Magnesium chloride (b) Calcium oxide
(c) Aluminium chloride (d) Calcium carbonate
Ques : Give one example of polyatomic cation and a polyatomic anion.
In a class of chemistry test which was based on observation some elements were provided named P, Q, R, S, T with the following data. Teacher informed the students that out of all these atoms it may be a noble gas, cation or anion. The teacher provided some information regarding that which is given in the table.
He has asked students to find the following:
(A) Find which elements are noble gas, anion, and cation respectively. (B) Symbolise the element
(C) Why do elements react?
OR
Ques: Salima and sheenu have a few doubts over the number of atoms in Helium Salima says Helium atom has 2 electrons and its valence shell but its valency is not 2. According to Sheenu Helium has 2 electrons and also its valency is 2. You are required to work as an arbitrator to solve the doubts of Salima and Sheenu. Similarly, they both have doubts of Salima and Sheenu. Similarly, they both have doubts regarding the valency and valence electrons of elements and are not able to recognize the difference between valence electrons and the valency. They have the following doubts.
(A) What is the valency of He?
(B) How many valence electrons does each noble gas have? (C) Why is the valency of inert gases zero?
(D) Why are noble gases unreactive in nature?
Ques : Write the atomicity of following molecules
a. Sulphur
b. Phosphorus
Ques : Write the Cations and Anions present in the following compound a. CH3COONa
b. NaCl
c. H2
d. NH4NO3Chapter 4 " Structure of atoms
Ques : The following questions consist of two statements – Assertion (A) and Reason(R). Answer these questions seleccting the appropriate option given below:
(a) Both A and R are true and R is the correct explanation of A (b) Both A and R are true but R is the correct explanation of A. (c) A is true but R is false
(d) A is false but R is true.
Ques :Assertion (A): The valency of aluminium is 3 and oxygen is 2.
Reason (R): The chemical formula of aluminium oxide is Al3O2
Ques : Assertion (A): The mass of the total number of protons and neutrons is a measure of the approximate mass of an atom.
Reason (R): The mass of an electron is negligible.
Ques : An atom with 3 proton and 4 neutron will have a valency of
(i) 3 (ii) 7 (c) 1 (d)4
Ques : Isotopes of an element have
(i) the same physical properties (ii) different chemical properties (iii) different number of neutrons (iv) different atomic numbers
Ques : Calculate the number of neutrons present in the nucleus of an element 'X' which is represented as 3115X.
Ques : The percentage of hydrogen in water is
a. 1.11%
b. 11.11%
c. 8.89%
d. 88.9%
Ques :An atom with 3 protons and 4 neutrons will have a valency of
a. 3
b. 4
c. 1
d. 7
Ques : Anode ray are produced when
a. Cathode is performed
b. Anode is performed’
c. When low voltage is passed
d. When pressure is high
Ques : The following questions consist of two statements – Assertion (A) and Reason(R). Answer these questions seleccting the appropriate option given below:
(a) Both A and R are true and R is the correct explanation of A (b) Both A and R are true but R is the correct explanation of A.
(c) A is true but R is false
(d) A is false but R is true.
Assertion (A) : Molecular weight of oxygen is 16
Reason (R) : Atomic weight of oxygen is 16
Ques : Composition of the nuclei of two atomic species X and Y are given as under:
Give the mass numbers of X and Y. What is the relation between the two species?
Ques : .One Electron is present in the outermost shell of the atom of an element X, what would be the nature of value of charge on the ion formed if this electron is removed from the outermost shell.
Ques :In the atom of an Element X, 6 Electrons are present in the outermost shell, if it acquires noble gas configuration by accepting requisite no of electron, then what would be the charge on the ion so formed.
Ques : The given figure depicts the atomic structure of an atom of an element ‘X’. Write the following information about the element ‘X’
(i) Atomic number of ‘X’ (ii) Atomic mass of ‘X’
(iii) Valence electrons (iv) Valency of ‘X’
(v) ‘X’ should be metal or non-metal
Ques : Read the text carefully and answer the questions:
Sulfuric acid or sulphuric acid, known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulphur, oxygen and hydrogen, with the molecular formula H2SO4. It is a colourless,odourless and viscous liquid that is miscible with water.
i. How many oxygen atoms are there in a molecule of sulphuric acid?
ii. Write a physical property of sulphuric acid.
iii. Whether the central atom in sulphuric acid belongs to a metal or a non-metal? Identify it.
OR
Calculate the number of atoms in one molecule of H2SO4? What type of molecule is it – monoatomic or polyatomic?.SAMPLE PAPER
KENDRIYA VIDYALAYA SANGATHAN
RANCHI REGION
(2022-23)
Science
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