Frank ICSE Chemistry Solutions

Frank ICSE Solutions for Class 9 Chemistry – Elements, Compounds and Mixtures

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Frank ICSE Solutions for Class 9 Chemistry – Elements, Compounds and Mixtures

PAGE NO :41
Solution 1:

  1. Elements: An element is a pure substance which can neither be broken down into simpler substances nor formed from two or more simpler substances by any known physical or chemical process. It is made of only one kind of atoms. It can be divided into four main categories
    1. Metals-Iron, magnesium
    2. Non-metals-Hydrogen, oxygen
    3. Metalloids-Arsenic, antimony
    4. Noble gas-Helium, neon
  2. Compound: A compound is a pure substance that is composed of two or more elements chemically combined in definite proportion by mass.
    The physical and chemical properties of a compound are different from those of its constituent elements.Hydrogen gas is combustible and oxygen is supporter of combustion , their  compound water  which is liquid is neither combustible nor a supporter of combustion.
  3. Mixture: Mixture is a physical combination of two or more substances, whether elements or compounds, which are mixed in any proportion by mass and retain their original properties even after mixing.
    Homogeneous mixture: They have same composition  and the same properties throughout their entire mass. Example- Salt solution, alloys etc.
    Heterogeneous mixture: They have different composition and different properties in different parts of their mass. Example-Mixture of sand and salt, mixture of iron fillings and sulphur etc.

Solution 2:

  1. Oxygen
  2. Carbon, hydrogen, Oxygen
  3. Mercury, Bromine
    1. Helium
    2. Oxygen
  5. Gallium,caesium
  6. Two noble gases are-
  7. Helium
  8. Argon

PAGE NO :42
Solution 3:
Air is a mixture because-

  1. The composition of air is not fixed i.e. the components may be present in any proportion by mass.
  2. Components of air i.e. nitrogen, oxygen etc. do not react with each other.

Solution 4:
Elements – Lead, Mercury, Sodium
Mixtures – Air, petrol, ink, gunpowder
Compounds – Common salt, alcohol, sand

Solution 5:
Pure substance – A pure substance is one which is made up of only one kind of particles. These particles may be atoms or molecules.
Example-Sulphur,  water.
Impure substance – They are mixtures of two or more chemically different substances mixed in indefinite proportions. The constituent substances retain their properties in the mixture.
Example-Mixture of salt and sand, gunpowder

Solution 6:
Mercury is the metal which is liquid at room temperature and bromine is the non-metal which is liquid at room temperature.

Solution 7:
Frank ICSE Solutions for Class 9 Chemistry - Elements, Compounds and Mixtures 1

Solution 8:
Frank ICSE Solutions for Class 9 Chemistry - Elements, Compounds and Mixtures 2

Solution 9:
Two reasons for believing that copper is a metal and sulphur is a non-metal are:-

  1. Copper is malleable and ductile while sulphur is neither malleable nor ductile.
  2. Copper is a good conductor of heat while sulphur is not good conductor of heat.

Solution 10:
Metalloids – The elements which possess properties intermediate between those of the metals and non-metals are called as metalloids. They react with both acids and alkali’s to form salts.
Ex – Arsenic, antimony

Solution 11:
Graphite is a non-metal which is a good conductor of electricity.

Solution 12:
Frank ICSE Solutions for Class 9 Chemistry - Elements, Compounds and Mixtures 3

Solution 13:
Mixture is the general name of the materials which contain atleast two pure substances and show the properties of their constituents.

Solution 14:

  1. Sodium
  2. Bromine
  3. Arsenic
  4. Radon
  5. Mercury
  6. Oxalic acid
  7. Carbon dioxide

Solution 15:
Frank ICSE Solutions for Class 9 Chemistry - Elements, Compounds and Mixtures 4

Solution 16:

  1. simpler substances
  2. atomic
  3. same
  4. mixture of salt and water
  5. two

Solution 17:
Names of two other mixtures which contain elements only are-

  1. Bronze
  2. Duralumin

Solution 18:

  1. A Molecule – The smallest particle of a substance that retains the chemical and physical properties of the substance and is composed of two or more atoms.
  2. Atomicity – Atomicity of an element is defined as the number of atoms present in one molecule of that element.

Solution 19:
Since, the constituents of a mixtures may be present in varying proportions so it cannot be expressed by a fixed chemical formula.

Solution 20:

  1. Air
  2. Cement
  3. Milk Sugar solution

Solution 21:
If a mixture of powdered iron and sulphur is heated in a test tube, a black shiny compound iron(II) sulphide (FeS)  is formed.

Solution 22:

  1. Tungsten, Mercury
  2. Graphite, Iodine

PAGE NO :43
Solution 23:
Frank ICSE Solutions for Class 9 Chemistry - Elements, Compounds and Mixtures 5

Solution 24:

  1. Chromatography – The chromatography is a technique of separating pure substances from the mixture.
    Advantages of chromatography –

    1. It requires a very small amount of the substance or sample.
    2. The components retain their individuality during the process.
    3. Chromatography finds application in easy separation of substances with similar physical and chemical properties.
  2. Filtration – It is a separation technique for separating a mixture in which one component should be solid and insoluble in the other liquid component.
    Example- Barium sulphate  in water.
  3. Fractional distillation – It is a technique used to separate  two liquids which dissolve in one another.The separation relies on the differences in boiling points of the two liquids.
    No, mixture of chloroform and water cannot be separated by this method.
  4. Centrifugation – It is a method for separating the suspended particles of a substance from a liquid in which the mixture is rotated at a high speed in centrifuge machine.
    Application – The clay particles in water (which are very fine) can be separated by centrifugation.

Solution 25:

  1. The vapour state which is obtained by heating solid without passing through liquid state is called sublimate.
  2. A liquid condensed from vapour in distillation is called distillate.
  3. The liquid produced after filtering a suspension of a solid in a liquid is called filtrate.
  4. Supernatant liquid is the upper layer of fluid found after a mixture has been centrifuged.
  5. If there is a heterogeneous mixture containing an insoluble solid in a liquid, then the solid substance that settle down is called sediment.

Solution 26:
We use fractional distillation to separate alcohol from a mixture of alcohol and water since the difference in boiling point between alcohol and mixture is very less.

Solution 27:

  1. We obtain pure water from sea water by distillation.
  2. A sample of pure iodine and sodium chloride is obtained by sublimation.

Solution 28:
The separation of the mixture depends upon-

  1. Size of the constituents
  2. Magnetic properties of constituents
  3. Mass of the constituents
  4. Solubility of the constituents
  5. Miscibilities of the constituents
  6. Boiling point of the constituents
  7. Diffusion rate of the constituents

Solution 29:
This is a separation technique of solid-solid mixture. This method involves the use of a solvent in which only one of the solid present in the mixture dissolves. Undissolved solid is removed by filtration. Mixture of ammonium chloride and silver chloride is separated by this method.

Solution 30:

  1. By distillation and fractional distillation we separate the mixture of two liquids.
  2. Yes, mixture of chloroform (B.P.= 61 oC) and carbon tetrachloride (B.P.=77 oC) be satisfactorily separated by the process of fractional distillation which is used for separating the various fractions of petroleum.
    For this purpose we will make two fractionating columns in the apparatus.

Solution 31:

  1. Solid-solid mixtures
    1. Magnetic separation method-Separation of iron ore from impurities
    2. Gravity separation-Mixture of saw dust and sand
    3. Solvent extraction-Mixture of sulphur and sand
  2. Solid- liquid mixtures
    1. Evaporation-Water and sodium chloride
    2. Distillation-Iodine in chloroform
    3. Filtration-Barium sulphate in water
  3. Liquid-liquid mixtures
    1. By separating funnel-Oil and water mixture
    2. Distillation-Acetone and water
    3. Fractional distillation-Ethyl alcohol and water

Solution 32:
The chromatography is the technique of separating pure substances from the mixtures. The chromatographic techniques was first employed by a Russian scientist Michael Tswett in 1903 for the separation of coloured substance from the mixture.
Principle of chromatography: The principle of chromatography is based on the difference in the extent of interaction (absorption) of various substances with a stationary phase and a mobile phase. A substance which interacts strongly with the mobile phase goes ahead of the other substance which interacts strongly with the stationary phase.

Solution 33:
Ink generally contain more than one dye. This mixture of ink is used as moving phase. Different constituents of ink move at different speed. The solvent rises up the filter paper over the spot and carries the different coloured components of ink to different heights on the filter paper. Each spot thus obtained at a particular height on the filter paper contains a particular constituent of the ink. Thus, the components of the ink are separated.

Solution 34:
By the help of fractional distillation we separate the components of liquid air.

Solution 35:

  1. Increase in weight – Sulphuric acid and iron
  2. Decrease in weight – Sodium carbonate crystals
  3. No change in weight – Sodium chloride

Solution 36:
By filtration, we will separate a mixture of chalk powder and water.

Solution 37:
Frank ICSE Solutions for Class 9 Chemistry - Elements, Compounds and Mixtures 6

Solution 38:
Fractionating column avoid the collection of distillate and re-distillation of distillate several times during fractional distillation.

Solution 39:
Two pair of liquids which can be separated by using a separating funnel-

  1. Oil and water
  2. Chloroform and water

Solution 40:
At first, with the help of magnet, iron nails will separate. Then, by sublimation camphor will separate from common salt.

Solution 41:
Frank ICSE Solutions for Class 9 Chemistry - Elements, Compounds and Mixtures 7
Frank ICSE Solutions for Class 9 Chemistry - Elements, Compounds and Mixtures 8

PAGE NO :44
Solution 42:

  1. When a magnet is moved over ‘X’, iron fillings are pulled away and stick to the magnet. When a magnet is moved over ‘Y’, it remained  unaffected.
  2. When’X’ is treated with carbon disulphide, sulphur dissolves but not iron. While, when’Y’ is treated with carbon disulphide, iron sulphide does not dissolve  but sinks to the bottom of the test tube.
  3. When ‘X’ is treated with dilute HCl, a colourless, odourless gas hydrogen is evolved which burns with a blue flame and is extinguished with a pop sound. While, when ‘Y’ is treated with dilute HCl, a colourless gas with the smell of rotten eggs is evolved which is H2S.
    There is difference in the behavior of ‘X’ and ‘Y’ because ‘X’ is a mixture while ‘Y’ is a compound. The component of a mixture do not react chemically, so retain their identity in the mixture while the components of compound react chemically, so do not retain their identity in the compound.

Solution 43:
Centrifugation is used in milk dairies to separate cream from milk dairies.

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Frank ICSE Solutions for Class 10 Chemistry – Chemical Bonding

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Frank ICSE Solutions for Class 10 Chemistry – Chemical Bonding

PAGE N0 : 39
Solution 1:
Chemical bond: A chemical bond may be defined as the linkage that stands for the force which actually holds the atoms together within the molecule.
Chemical bonding: The phenomenon during which a chemical bond is formed is called chemical bonding.

Solution 2:
Atoms combine to attain the electronic configuration of nearest inert gases as the atoms of inert gases are very stable having 8 electrons or duplet (or 2 electrons in case of helium atom) in their outermost shell.

Solution 3:
Electrovalent compounds: The chemical compounds containing electrovalent bonds are called electrovalent or ionic compounds.
For example: Sodium chloride (NaCl).
Covalent compounds: The chemical compound, formed as a result of mutual sharing of electrons or electron pairs thereby establishing a covalent bond is called a covalent or molecular compound.
For example: Hydrogen molecule (H2)

Solution 4:
The conditions for the formation of an electrovalent bond are:

  1. Low ionization energy of electropositive atom
  2. High electron affinity of the electronegative atom.
  3. Large electronegativity difference.
  4. High lattice energy.
    Concept Insight:

    • Lower is the ionization energy of atom, higher is its tendency to lose electron to form a cation and form ionic bond.
    • Higher the value of electron affinity of an atom, greater will be its tendency to form anion and form ionic bond.
    • If the electronegativity difference of two elements is higher, more easy will be the transfer of electrons and hence more chances of ionic bond formation.
    • Lattice energy is the energy released when positive and negatively charged atoms called ions come closer to form a crystal because the attractive forces among the oppositely charged ions tend to decrease the energy of the system. Higher is the lattice energy, greater will be the ease of formation of the compound.

Solution 5:

Frank ICSE Solutions for Class 10 Chemistry - Chemical Bonding 1

Solution 6:
Hydrogen chloride has a polar covalent bond because in hydrogen chloride the higher electronegativity of chlorine atom attracts the shared electron pair towards itself. As a result, the chlorine atom gets a partial negative charge while the hydrogen atom gets a partial positive charge. Hence such a covalent bond with charge separation is called polar covalent bond.
While methane has a non polar covalent bond because in case of methane molecule the shared electron pairs are at equal distance from the carbon and hydrogen atoms, because neither the carbon atom nor the hydrogen atom has enough electronegativity difference between each other to attract the shared pairs of electrons towards itself. Hence no charge separation occurs in the covalent bond due to which it is called non polar covalent bond.
Concept Insight: When a covalent bond is formed between the atoms of the same elements of equal electronegativity then the electron pairs are shared equally between the atoms and the bond so formed is called non polar covalent bond. On the other hand, if the covalent bond is formed between atoms of different elements, with difference in electro negativity, the electrons are not shared equally between the atoms. The more electronegative atom pulls the bonded pair of electrons towards itself and acquires negative charge while the other less electro negative atom acquires positive charge and the bond becomes polar covalent bond.

Solution 7:
In terms of electron transfer, oxidation is defined as the phenomenon in which an atom loses electron to form a positively charged cation while reduction is defined as the phenomenon in which an atom gains electron to form a negatively charged ion called anion.
During formation of ionic bond one atom undergoes oxidation while another atom undergoes reduction.

PAGE NO : 48
Solution 8:
Frank ICSE Solutions for Class 10 Chemistry - Chemical Bonding 2

Solution 9:
Frank ICSE Solutions for Class 10 Chemistry - Chemical Bonding 3

Solution 10:

  1. Sodium chloride dissolves in water because it is an ionic compound and water is also a polar covalent compound. Water decreases the electrostatic forces of attraction among the sodium and chloride ions due to which these ions become free in water, hence sodium chloride dissolves.
    On the other hand, carbon tetra chloride has non polar covalent bond and water has polar covalent bond. Hence, water is unable to break the non polar covalent bond of carbon tetra chloride. So it is insoluble in water
  2. Helium does not form He2 molecule as it has its outermost shell complete i.e. two electrons in its valence shell. Due to this complete valence shell helium atom is very stable hence does not participate in chemical bonding to form  He2 molecule.
  3. Pure water does not conduct electricity because it has a polar covalent molecule hence does not have ions in it which can conduct electricity.
    On adding sodium chloride to pure water, sodium chloride breaks apart into sodium and chloride ions because water being polar decreases the strong forces of attraction among sodium and chloride ions. Now, pure water has ions present in it which can conduct electricity.
  4. Cl2 is a non polar molecule because the bond is between same atoms that is chlorine with zero electronegativity difference among them. So the shared electron pair is attracted equally by the two chlorine atoms hence there is no separation of charges in the bond formed so the chlorine molecule is non polar.
  5. In case of HCl the bond is formed between two different atoms that is hydrogen and chlorine with enough electro negativity difference so that the shared electron pair is attracted towards more electronegative chlorine atom which acquires partial negative charge while the hydrogen atom acquires partial positive charge hence HCl is a polar molecule.
  6. Metals have low ionization energy due to which they can lose their outermost electrons easily to form positive metallic ions hence metals are electropositive.
    For example Sodium metal always form Na+ions, Potassium forms K+ ions etc.

Solution 11:

  1. (i) when the electro negativity difference between the two atoms is high then the bond formed will be purely ionic.
    (ii) When the electro negativity difference between the two atoms is low then the bond formed will be polar covalent bond.
    (iii) When the electro negativity difference between the two atoms is zero then the bond formed will be purely covalent.
  2. Ionic compounds = NO, NH4Cl, NH4NO3
    Covalent compounds = N2, NH2 , NO
    Polar compounds = NCl3

Concept Insight: Electro negativity difference between the bonded atoms determines the ease of transfer of electrons between the atoms. On the basis of extent of transfer of electrons between the two atoms the bond will be ionic, covalent or polar.

Solution 12:
Frank ICSE Solutions for Class 10 Chemistry - Chemical Bonding 4

Solution 13:

  1. MgCl2, CaCl2.
  2. Urea, Glucose.
  3. CH4, benzene.
  4. SO2, H2S
  5. H2, N2

Solution 14:
The necessary conditions for the formation of covalent molecule are:

  1. Number of valence electrons: Both the participating atoms should have four or more valence electrons in their valence shell.
  2. Equal electro negativities: The combining atoms should have equal electro negativities so that no transfer of electrons takes place.
  3. Equal electron affinities: The combining atoms should also have equal electron affinities i.e. equal attraction for electrons.
  4. Ionization energy: It should be high for both the atoms so that there is no chance of removal of electrons.
  5. High nuclear charge and small inter nuclear distance: Both these conditions favor the formation of covalent bond because during the formation of a covalent bond the electron density gets concentrated between the nuclei of the combining atoms and this electronic charge is responsible for holding the two nuclei together.
    The properties of covalent compounds are:
  6. Nature: They are generally volatile liquids or gases. Some may be gases like urea, sugar etc.
  7. Low melting and boiling points: Since the intermolecular forces of attraction are weak, very small amount of heat energy is required to overcome these forces hence their melting and boiling points are low.
  8. Electrical conductivity: Since covalent compounds are made up of molecules and not ions, so they do not conduct electricity.
  9. Solubility: These are insoluble in water but soluble in organic solvents.
  10. Ionization in solution: These do not ionize when dissolved in water except some polar covalent compounds like HCl.
  11. Molecular reactions: These participate in reactions as a molecule so the reactions are called molecular reactions. These are slow reactions.

Solution 15:
Coordinate bond: The bond formed between two atoms by a pair of electrons, provided entirely by one of the combining atoms, is called a coordinate bond or dative bond.
Conditions for the formation of coordinate bond:

  1. One of the two atoms must have at least one lone pair of electrons.
  2. Another atom should be short of at least a lone pair of electrons.

Solution 16:
Lone pair: A pair of electrons which is not shared with any other atom is known as the lone pair of electrons.
For example in NH3, Nitrogen has a lone pair of electrons which is not shared with any hydrogen atom.
Shared pair: A pair of electrons which is shared with other atoms to form a bond is known as shared pair of electrons.
For example in HCl the pair of electrons responsible for bond formation between H and Cl is called shared pair.

Solution 17:
Frank ICSE Solutions for Class 10 Chemistry - Chemical Bonding 5

Solution 18:

  1. The forces of attraction between the molecules of covalent compounds are weak because the molecules are neutral. So, they are generally gases or liquids or soft solids.
  2. Covalent compounds have low melting and boiling point because the intermolecular forces of attraction among the molecules of covalent compounds are weak. Hence very small amount of heat energy is required to overcome the attraction between the molecules.
  3. On the basis of principle like dissolves like we can interpret the insolubility of non polar covalent compounds. Since water is a polar covalent compound that is it has positively and negatively charged ends but the non-polar covalent compounds do not have any kind of charge separation. So water molecules are unable to interact with the molecules of non polar compound and break apart the intermolecular forces of attraction among non-polar molecules making them soluble in water.
  4. Polar covalent compounds are good conductors of electricity because when these are dissolved in water, they ionize and act as electrolyte to produce ions which are responsible for conduction of electricity.
    Frank ICSE Solutions for Class 10 Chemistry - Chemical Bonding 11
    For example polar covalent compound HCl in water behaves as:
    These hydronium and chloride ions produced on dissolution of HCl in water are responsible for conduction of electricity.

PAGE NO : 41
Solution 2002-1:
Frank ICSE Solutions for Class 10 Chemistry - Chemical Bonding 6

Solution 2004-1:
Frank ICSE Solutions for Class 10 Chemistry - Chemical Bonding 7

Solution 2005-1:
Frank ICSE Solutions for Class 10 Chemistry - Chemical Bonding 8

PAGE NO : 42
Solution 2006-1:
Frank ICSE Solutions for Class 10 Chemistry - Chemical Bonding 9

Solution 2006-2:

  1. (b)
  2. (a)

Solution 2007-1:
Frank ICSE Solutions for Class 10 Chemistry - Chemical Bonding 10

Solution 2008-1:
ionises when dissolved in water

Solution 2008-2:

  1. Covalent bond.
  2. Co-ordinate bond

Solution 2009-1:

  1. solid
  2. low

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Frank ICSE Solutions for Class 9 Chemistry – Study of Gas Laws

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Frank ICSE Solutions for Class 9 Chemistry – Study of Gas Laws

PAGE NO :21
Solution 1:
An ideal gas can be characterized by three state variables:

  1. Absolute pressure (P),
  2. Volume (V), and
  3. Absolute temperature (T).

Solution 2:
Frank ICSE Solutions for Class 9 Chemistry - Study of Gas Laws 1

Solution 3:
Frank ICSE Solutions for Class 9 Chemistry - Study of Gas Laws 2

Solution 4:
Frank ICSE Solutions for Class 9 Chemistry - Study of Gas Laws 19

Solution 5:
Kelvin zero is – 273.15 oC.

Solution 6:
Frank ICSE Solutions for Class 9 Chemistry - Study of Gas Laws 3

Solution 7:
The standard temperature and pressure (STP) by general convention are 0 oC(273 K) and 1 atm(760 mm Hg).

Solution 8:

  1. The value of standard temperature is (i) 0 oC and (ii) 273 K
  2. The value of standard pressure is (i) 1 atm, (ii) 760 mm of Hg, (iii)76 cm of Hg, (iv)760 torr

Solution 9:
Frank ICSE Solutions for Class 9 Chemistry - Study of Gas Laws 4

Solution 10:
Frank ICSE Solutions for Class 9 Chemistry - Study of Gas Laws 5
Frank ICSE Solutions for Class 9 Chemistry - Study of Gas Laws 6

Solution 11:
Frank ICSE Solutions for Class 9 Chemistry - Study of Gas Laws 7

Solution 12:
There is simultaneous effect of temperature and pressure changes on the volume of a given mass of a gas. So, when stating the volume of a gas, the pressure and temperature should also be given.

PAGE NO :22
Solution 13:
Frank ICSE Solutions for Class 9 Chemistry - Study of Gas Laws 8

Solution 14:

  1. Volume of a gas would be reduced to zero at 0 K (-273 0C).All temperatures on the Kelvin scale are positive, so Kelvin scale has been adopted for chemical calculation.
  2. At absolute zero temperature, volume of a gas would be reduced to zero. Theoretically,this is the lowest temperature that can be reached. At this temperature all molecular motions cease. Thus, practically this temperature is impossible to attain because on cooling gases liquefy and Charles’ law is no more applicable.
  3. According to combined gas law equation, there is simultaneous effect of temperature and pressure changes on the volume of a given mass of a gas. So, when stating the volume of a gas, the pressure and temperature should also be given.

Solution 15:
Frank ICSE Solutions for Class 9 Chemistry - Study of Gas Laws 9

Solution 16:
Frank ICSE Solutions for Class 9 Chemistry - Study of Gas Laws 10

Solution 17:
Frank ICSE Solutions for Class 9 Chemistry - Study of Gas Laws 11

Solution 18:

  1. True
  2. False
  3. False
  4. False
  5. False

Solution 19:
Frank ICSE Solutions for Class 9 Chemistry - Study of Gas Laws 12

Solution 20:
Frank ICSE Solutions for Class 9 Chemistry - Study of Gas Laws 13

Solution 21:
We trap a definite quantity of  air in the closed vessel. At any point, the pressure on the air is equal to the atmospheric pressure plus the pressure due to the excess mercury column in the open end tube. By pouring mercury in the tube, we increase the pressure on the air and measure its volume under that pressure. We thus obtain a set of data for the volume of a fixed mass of air under different pressures.
For a given mass of air at constant temperature, the following observations are made-

  1. The volume of air decreases with increasing pressure and vice versa.
  2. The proportion by which the volume decreases or increases is the same by which the pressure increases or decreases.

Solution 22:

  1. Pressure will also be doubled.
  2. Pressure will be double.

Solution 23:

  1. 273
  2. absolute zero
  3. absolute temperature
  4. the average kinetic energy

Solution 24:
Frank ICSE Solutions for Class 9 Chemistry - Study of Gas Laws 14

Solution 25:
Frank ICSE Solutions for Class 9 Chemistry - Study of Gas Laws 15

Solution 26:
Frank ICSE Solutions for Class 9 Chemistry - Study of Gas Laws 16

Solution 27:
Frank ICSE Solutions for Class 9 Chemistry - Study of Gas Laws 17

Solution 28:
As weather balloon go higher into the atmosphere, the air becomes less dense, so air pressure drops. Because of this, the air that is already inside the balloon  expands to cope with the difference in pressure. The end result is that the balloon expands making it larger.

Solution 29:
Frank ICSE Solutions for Class 9 Chemistry - Study of Gas Laws 18

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Frank ICSE Solutions for Class 9 Chemistry – Matter and its Composition: Law of Conservation of Mass

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Frank ICSE Solutions for Class 9 Chemistry – Matter and its Composition: Law of Conservation of Mass

PAGE NO :8
Solution 1:
Matter is anything around us which occupies space and has mass. Example- Coal, Copper, Water, Oxygen, Kerosene
Key: Matter occupies space and has mass.

Solution 2:
The conditions for something to be called matter are –

  1. It should occupy space.
  2. It should have mass.

Solution 3:
Light and sound are not considered to be matter because they neither have mass nor do they occupy space.

PAGE NO :9
Solution 4:
Solid:

  1. The particles are held together by strong intermolecular forces and have minimum intermolecular space.
  2. Solids have definite mass, shape and volume.

Liquid:

  1. The intermolecular forces of liquid molecules are intermediate of molecules  of solids and gases while intermolecular spaces are greater than in solids.
  2. Liquids have definite mass and volume but not definite shape. They take the shape of the container.

Gas:

  1. The particles are held together by very weak intermolecular forces while intermolecular spaces are much greater than in solids.
  2. Gases have definite mass but not definite shape and volume. They take the shape of the container.

Solution 5:
Two reasons for saying that wood is a solid are-

  1. Wood has definite mass and shape.
  2. Their intermolecular forces are very strong so they cannot flow.

Solution 6:
The particles of gases are separated from each other by large spaces and intermolecular forces of attraction are the weakest in gases. They have least density. So, they can flow easily. Hence, gases have no fixed shape and volume.
Key: Intermolecular forces of attraction are the weakest in gases.

Solution 7:

  1. Gases
  2. Solid
  3. Solid

Solution 8:

Properties Solids Liquids Gases
1.State of packing The particles are closely packed and their positions are also fixed. The particles are loosely packed and their positions are not fixed. The molecules are wide apart and their positions are also not fixed.
2.Energy associated Particles can vibrate only to and fro about their mean positions. Therefore, they have small kinetic energy due to their motion. The particles can move about more freely and have considerable kinetic energy due to their motion. The particles move about freely and have maximum kinetic energy due to their motion.
3.Intermolecular forces The particles are held together by strong intermolecular forces. The particles are held together by weak intermolecular forces. The particles are held together by very weak intermolecular forces.
4.Physical features Solid has a crystalline structure with both definite size and definite shape. Liquid does not have a definite shape but has definite volume and can flow from higher to lower level. Gas has neither definite shape nor a definite volume but can flow and is easily compressible.

Solution 9:

  1. gases
  2. strong
  3. sublimation
  4. Condensation
  5. gaseous

Solution 10:
The postulates of the kinetic theory of matter-

  1. Composition of Matter: Matter, whether in the solid, liquid or gaseous state, is composed of very small particles which may be molecules, atoms or ions.
  2. Arrangement of Particles: These particles have spaces lying between them and these spaces are referred to as intermolecular spaces or interparticle spaces.
  3. Forces of Attraction: The forces of attraction between the molecules of a given substance are called intermolecular forces. The magnitude of this force depends upon the state of the substance and on the magnitude of the intermolecular spaces. As the intermolecular space increases, the intermolecular force decreases.
  4. Motion of the constituent particles: The particles are always in a state of motion. In solids, they vibrate about their mean positions and in liquids and gases, they move randomly.
  5. The kinetic energy of the particles increases with rise in temperature. As the temperature is increased, the particles undergo motion more vigorously and more  randomly.

Solution 11:

  1. Solid to liquid state: The conversion of a substance from the solid state to liquid state at a particular temperature is called melting or fusion. The heat energy supplied to the solid is absorbed by its molecules to gain kinetic energy. The kinetic energy increases the rate of vibration of the molecules. The force of attraction thus no longer holds the molecules close together and the solid gets change into liquid.
  2. Gas to liquid: The conversion of a substance from the gaseous state to its liquid state at a particular temperature is called condensation or liquefaction. On cooling, the gas molecules loose their kinetic energy in the form of lost heat and so molecular motion slows down. Decreased molecular motion causes a decrease in intermolecular space. The molecules come very close and the force of attraction between them correspondingly increases and the gas gets change into liquid.
  3. Liquid to gaseous state: The heat energy supplied to the liquid is absorbed by its molecules to gain kinetic energy and therefore the molecules move faster. This increases the intermolecular space. The intermolecular force of attraction decreases and liquid changes into gaseous state.
  4. Liquid to solid state: The conversion of a substance from the liquid state to solid state by cooling is called freezing. On cooling a liquid, the kinetic energy of the molecule is decreased. Due to decreased kinetic energy, the molecules cool down and come closer, thus reducing the intermolecular spaces. The force of attraction between the molecules thus increases. Now, the molecules are no longer in a position to be free or to migrate and liquid changes into a solid.

Solution 12:

  1. Freezing: The process of changing a liquid into a solid by cooling is called        freezing. Freezing means solidification. It occurs at a definite temperature called freezing point.
  2. Evaporation: The phenomenon involving the change of a substance from the liquid state to the gaseous state at room temperature or at any other temperature below its boiling point is called vaporization or evaporation.
  3. Boiling point: The temperature at which a liquid boils and changes rapidly into a gas at atmospheric pressure is called boiling point of the liquid.
  4. Melting point: The temperature at which a solid substance changes into its liquid state at 1 atmospheric pressure is called the melting point of that substance.

Solution 13:

  1. Size of naphthalene balls decreases – Sublimation
  2. Drying of wet clothes – Evaporation
  3. Wax melts in the sun – Melting
  4. Formation of clouds – Evaporation and Condensation

Solution 14:
Three compounds which are sublimate are-

  1. Camphor
  2. Naphthalene
  3. Iodine

Solution 15:
‘States of matter triangle’ shows inter-conversion of states of matters.
Frank ICSE Solutions for Class 9 Chemistry - Matter and its Composition Law of Conservation of Mass 1

Solution 16:
The process by which a liquid slowly converts into vapour state at a temperature below its boiling point is called evaporation.
The heat energy is absorbed by the liquid to convert it into vapour state. So, loss of heat causes cooling.

Solution 17:

  1. True
  2. True
  3. False
  4. True

Solution 18:
“In all physical and chemical changes, the total mass of the reactants is equal to that of the products”. So, in other words matter can neither be created nor destroyed.

Solution 19:
Frank ICSE Solutions for Class 9 Chemistry - Matter and its Composition Law of Conservation of Mass 2

Solution 20:

  1. Matter
  2. Solid
  3. Gas
  4. Solid
  5. Gas
  6. Gas
  7. Liquid
  8. Fluid
  9. Melting
  10. Vaporization

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Frank ICSE Solutions for Class 10 Chemistry – Periodic Properties and Variation of Properties

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Frank ICSE Solutions for Class 10 Chemistry – Periodic Properties and Variation of Properties

PAGE NO : 16
Solution 1:
Modern periodic law states that the physical and chemical properties of elements are a periodic function of their atomic numbers i.e., if the elements are arranged in the order of their atomic numbers, the elements with similar properties are repeated after definite regular intervals.
Concept Insight: The elements are characterized by their atomic number as well as atomic weight. Modern periodic law uses atomic number which is number of protons or number of electrons present in an atom of an element.

Solution 2:
Modern periodic table consists of eighteen groups and seven periods.
Concept Insight: Classification of elements on the basis of increasing atomic number is known as Modern Periodic Table. The vertical columns are called groups and the horizontal rows are called periods.

Solution 3:
The recurrence of similar properties of elements after certain regular intervals when they are arranged in the order of increasing atomic numbers is called periodicity.
Concept Insight: Periodicity in properties is due to the repetition of similar outer electronic configuration of elements at certain regular intervals.

Solution 4:
In general, the elements belonging to a group have the same number of valence electrons .For example, all the group 1 elements have valency one since they have only one electron in their outermost shell.
In general, the elements belonging to a period do not have same valency but their valence shell remains the same. For example, second period has 8 elements with atomic number 3 to 10 but in all of them the valence electrons are present in shell number two.
Concept Insight: For elements in a group the number of electrons present in the outermost shell is the same and therefore the elements have same valency and or elements in a period number of electrons present in the outermost shell of elements in a period increase from left to right but the shell does remains the same.

Solution 5:
Fluorine has lower electron affinity than chlorine because of the small size of fluorine which results in stronger repulsion between the electron and the electrons already present in the atom of fluorine. Hence the energy released in accepting an electron is lesser in fluorine than that of chlorine.
Concept Insight: For answering this question you should recall that electron affinity is the energy released when an electron is added to an isolated gaseous atom to form an anion. Due to small size of fluorine atom, the valence shell is already crowded, hence when an electron is added to a fluorine atom in gaseous state there occurs strong repulsion between the added electron and those already present in the atom hence less amount of energy is released.

Solution 6:

  1. The element with highest first ionization energy: Neon (Ne)
  2. The element with highest electro negativity: Fluorine (F)
  3. The element with largest atomic size: Lithium (Li)
  4. The most reactive non-metal: Fluorine
  5. The most reactive metal: Lithium
  6. Concept Insight:
    • Neon has highest ionization energy since it is a noble gas and has its octet complete which makes it very stable.
    • Fluorine has highest electronegativity as we know that electro negativity increases along a period due to decreasing atomic size and increasing nuclear charge.
    • Lithium has the largest atomic size since it is an alkali metal i.e., belongs to group 1 and we know that as we move from left to right in a period atomic size decreases. So lithium has largest size while fluorine has smallest size in second period.
    • Fluorine is most reactive non metal as it requires only one electron to complete its octet and become stable.
    • Lithium is the most reactive metal as it can complete its octet by losing its single electron present in its outermost shell.

PAGE NO : 17
Solution 7:

  1. The most metallic element will be found at C.
  2. The most non-metallic element will be found at D.

Concept Insight: For answering this question you should recall metallic character increases down the group and also increases with the increasing size of the atom. Since elements of group 1 has largest atomic sizes among all the elements of periodic table so the most metallic element belongs to group 1.
Similarly, non-metallic character decreases down the group and increases with the decreasing size of atom.

Solution 8:
Frank ICSE Solutions for Class 10 Chemistry - Periodic Properties and Variation of Properties 1

Solution 9:

  1. 18, 7.
  2. First.
  3. Seventeen.
  4. Electron affinity.
  5. Decrease, increase
  6. Fluorine
  7. Zero.

Solution 10:

  1. False.
  2. True.
  3. True.
  4. True.
  5. True.
  6. True.

Concept Insight: (i) There is inverse relation between atomic size and electron affinity. More is the size, less is the electron affinity and vice versa because more is the size of atom, more is the distance between the nucleus and last shell to which electron enters. This results in decrease in force of attraction between the nucleus and incoming electron and hence the electron affinity decreases. Fluorine has smaller size than chlorine so it must have less electron affinity than chlorine.

Solution 11:

  1. Li < Be < B
  2. I < Br < F < Cl
  3. SiO2 < P2O5 < SO3 < Cl2O7
  4. I+ < I < I–

Concept Insight:

  1. Li, Be, B belongs to second period and ionization energy increase as we move left to right in a period due to increased nuclear charge and decrease of atomic size.
  2. Electron affinity decreases down the group due to increase in atomic size as it results in more distance between nucleus and last shell to which incoming electron enters. Hence, incoming electron feels less attraction from the nucleus.
  3. In a period, acidic nature of oxide increases.
  4. Size of a cation is always smaller than the corresponding atom due to decrease in number of electrons and increase in effective nuclear charge i.e., greater force of attraction by the nucleus on the electrons.
    Size of an anion is always more than the corresponding atom due to decrease in effective nuclear charge i.e., lesser force of attraction by the nucleus o the electrons.

Solution 12:
The statement that in each period, the atomic size gradually decreases with increase in atomic number means that as move from left to right in a period, nuclear charge increases by one unit in each succeeding element while the number of shells remains the same. Due to this increased nuclear charge, the electrons of all the shells are pulled closer to the nucleus thereby bringing the outer most shell closer to the nucleus. With the result, the atomic size decreases across a period.
For example, in the second period from lithium to fluorine, lithium has the largest size while fluorine has the smallest size.

Solution 13:
In the case of noble gases or inert gases there are exceptions and the atomic radius or size of the elements are greater than the other elements of the period to which these elements belong.

PAGE NO : 18
Solution 14:
As we move down a group, the atomic radii increase because a new shell is added at each succeeding element though the number of electrons in the outer most shell remains the same. Thus, the atomic size of elements increases in size downward.
Although nuclear charge also increases in going down the group but the effect of nuclear charge on atomic size is much less than the increase due to addition of a new shell.
In group 17, the atomic size follows the trend:
F < Cl < Br < I

Solution 15:
The elements of third period are:
Na, Mg, Al, Si, P, S, Cl, Ar
The most metallic element is sodium i.e., Na and the most non-metallic element is chlorine i.e., Cl.
Concept Insight:
In a period, metallic character decreases on moving from left to right because of decrease in size of atom due to which elements cannot lose electron easily.

Solution 16:
Frank ICSE Solutions for Class 10 Chemistry - Periodic Properties and Variation of Properties 2

Solution 17:
Frank ICSE Solutions for Class 10 Chemistry - Periodic Properties and Variation of Properties 3

Solution 18:
Electron affinity is the energy released when an electron is added to an isolated gaseous atom to form the negative ion (anion).
Unit: Its units are electron volt (eV).
Its SI units are Kilojoules per mole(KJmol)-1

Solution 19:
Out of A and B, A will ionize more easily to form a negative anion because of the high value of electron affinity, energy released during addition of electron will be high hence the resulting anion formed will be more stable than the corresponding atom.

Solution 20:

  1. Larger the atomic size, farther is the valence electron from the nucleus and lesser is the pull exerted on it. As a result, electron can be easily removed from the valence shell and hence more metallic is the element.
  2. Halogens need only one electron to complete their octet and become stable their atomic size is very less hence the distance between their last shell and nucleus is very less, as a result the force of attraction between the nucleus and the incoming electron is less and hence the electron affinity is high for halogens.
  3. When an atom loses or gain electron to form ion, the number of electrons present in the outermost shell also changes. Corresponding to that effective nuclear charge on the changed number of electrons also change which further changes the size of an atom as there is inverse relation between effective nuclear charge and size of atom.
  4. K and Li belongs to group 1 i.e., metals and we know that for metals chemical reactivity of elements increases down the group because chemical reactivity increases as electropositive or metallic character increases.
  5. The electronegativity of chlorine is higher than sulphur because both of them belong to third group and chlorine follows sulphur. We know that, within a period electronegativity increases as we move from left to right because of decrease in atomic size and increase in nuclear charge.
  6. Group 17 elements are non metals because they have 7 electrons in their valence shell and ionize by accepting 1 electron to form an anion.
    For example group 17 elements F, Cl, Br and I all have 7 electrons in their valence shell and ionize by accepting 1 electron to form F–, Cl–, Br– and I–.
    Group 1 elements are metals because they have tendency to lose the one electron present in their valence shell and form positive ion.
    For example, group 1 elements Li, Na, K, Rb, Cs have tendency to lose the one electron present in their valence shell and form positive ions Li+., Na+., K+., Rb+.and Cs+.

Solution 21:

  1. (C) i.e. 2, 8, 2 because it has only 2 electrons in its valence shell which can be lost to form a di positive cation.
  2. (C) i.e. 0.72, 0.72
  3. (d) i.e. element forms basic oxide because the element is a metal as it has valency 1.
  4. (a) i.e. F because it belongs to group 17 whose elements have valency 7 and thus requires only 1 electron to complete their octet.

Solution 2000-1:

  1. Number of elements in period 1 = 2
    In period 2 = 8
    In period 3 = 8.
  2. Elements in period 1 are Hydrogen (H) and Helium (He).
  3. Atomic size of elements decreases on moving from left to right in a period.

Solution 2000-2:

  1. The elements at the end of period 2 and period 3 both have their outermost shell complete and belong to noble gases.
  2. An element in group 7 is likely to be non metallic in character since group 7 element will have 7 electrons in its valence shell.
  3. Metallic.

PAGE NO : 19
Solution 2001-1:

  1. Atomic number.
  2. Period, non-metallic.
  3. More.
  4. Number of outer electrons.

Solution 2002-1:
A group is a vertical column of elements having the same number of valence electrons and same valency in the periodic table. There are 18 groups in the periodic table.

Solution 2002-2:
Within a group the element with the greatest metallic character and largest size is expected to be present at the bottom of the group.

Solution 2002-3:
Ionization potential decreases down the group because atomic size increases down the group which decreases the effective nuclear charge over the valence electron which further can now be removed easily.

Solution 2002-4:
There are 8 elements in period 2.

Solution 2003-1:

  1. Al2(SO4)3
  2. Covalent.
  3. The elements of group VIIA all have same number of electrons in their valence shell and same valency.
  4. Neon
  5. 8 electrons are present in the valence shell of the element with atomic number 18.
  6. Electron affinity.
  7. Electronic configuration of element in the third period which gains one electron to become an anion is 2, 8, 7.
  8. Decreases, number of valence shell electrons/outermost shell electrons, valence shell/ outermost shell.

PAGE NO : 20
Solution 2004-1:

  1. Na Mg Al Si P S Cl.
  2. (a) lower, higher.
  3. remains the same.

Solution 2005-1:

  1. b
  2. d
  3. c
  4. a
  5. c

Solution 2006-1:

  1. Second period.
  2. Nitrogen. It should be placed between oxygen andcarbon.
  3. Beryllium < nitrogen < fluorine
  4. Fluorine (F)

Solution 2007-1:

  1. Thallium
  2. Boron
  3. 3
  4. BCl3
  5. The elements in the group to the right of this boron group will be less metallic in character because on moving to the right of the periodic table metallic character decreases as ionization energy deceases and tendency to lose electron also decreases.

Solution 2008-1:

  1. False
  2. True
  3. False
  4. True

Solution 2008-2:

  1. (i) First element in period 2 is Lithium and last element is Neon.
    (ii)Atomic size increases on moving from top to bottom of a group.
    (iii)Chlorine among halogens has the greatest electron affinity.
    (iv) All elements in group 7 have same number of valence shell electrons.
  2. (i) metallic
    (ii) smallest
  3. (i) Ba i.e. Barium will form ion most readily since it is at the bottom of a group its ionization energy is low because its atomic size is more. Due to this effective atomic charge of nucleus over the valence shell electron is least and it can be removed easily.
    (ii) Electro negativity of an element measures the capacity of an element to attract the shared pair of electrons in a bond towards itself.

Solution 2009-1:
(d) Fluorine

PAGE N0 : 22
Solution 2009-2:
Frank ICSE Solutions for Class 10 Chemistry - Periodic Properties and Variation of Properties 4

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